I want to be a Mechanical Design Engineer, so I have started learning Solidworks. But there are a lot of things in front of me like molding,sheet metal, simulation etc. Can u give me Suggestions and guidelines please??

It really all depends on where you are starting from. Solidworks is a great tool, but all that FEA stuff will make a good engineer better and a bad engineer worse. The books suggested above give you a good overview of mechanical engineering as a discipline.

If you are coming out of high school with some decent math skills (calculus, vector calc, diff eq), then you are in a good place. Additionally, newtonian physics is a foundation for basically all of mechanical engineering. Make sure you’ve got those down. Then I would recommend diving into statics, dynamics, and mechanics of materials. Solidworks can be an excellent guide along side of those subjects for more of an applied approach.

Solidworks is a design tool. You can use it to be a designer; however, to be an engineer you need to understand a lot more than just how to make something (though that’s a big part of it).

Hi @Sazid Islam Purno!
I totally agree with what @cmalco and @Chris Hainley said. In addition, I suggest a "priority list" that I developed in my professional activity as a designer of heavy machinery for the steel industry. I came to the conclusion that the different physical phenomena that affect machinery do so at different times and, therefore, can be ordered from the most urgent to the slowest. On the other hand, it is "fundamental to understand which variables control them" since, when you start adjusting the static response, for example, if you later have impact problems you will not touch the same parameters, and if after adjusting the impact response you have problems with vibrations, fatigue, etc. you should also identify the parameters that control them and try not to "undo" the good responses achieved previously!

The image that I share with you first "states the phenomena to attend to in the suggested order". Below I share the translation of the text of that figure. I am also sharing a pdf (unfortunately it is only in Spanish) that is incomplete because I suspended its elaboration, but in any case it has developed the first phenomena that serve to understand the reasons for making this "mechanical designer's priority list".
Hope this can help you!
Kind regards

----------------------- Figure MEV00.png -----------------
Machine Designer's Priority List
The following list reflects various aspects related to the design of machines, ordered according to how they appear before and during their useful life. These are issues that the designer must deal with, although not simultaneously, manipulating the appropriate variables for each phenomenon. For this reason they are classified as short, medium and long term, trying to address them in the same order in which they appear as possible problems.
► DESIGN SPECIFICATIONS...(short term)...identify the need and desired useful effect
► KINEMATICS and DYNAMICS...(short term)...movement and circulation of power
► CONSTRUCTION and ASSEMBLY...(short term)...achievable and assembleable geometries
► STATIC...(short term)...strength, stiffness and stability
► IMPACT...( short term)...non-quasistatic application of loads
► VIBRATIONS...(medium term)...synchronism between excitations and own movements
► FATIGUE ...(medium term)...accumulation of damage before cyclical loads
► WEAR...(medium term) ...friction / lubrication damage
► CORROSION...(medium term)...adverse chemical reactions
► AGING...(long term)....loss of material properties
► SLOW FLOW...(long term)...plastic deformation over long periods of time
► OTHER PHENOMENA....(long term)...effects not solvable by design
► MAINTENANCE...(long term)...corrective, preventive and predictive
This list can be thought of as a series of “tests to be passed by the design” where each prompts the designer to make decisions that, if possible, should not affect pre-set parameters for already passed tests. In other words, we try to address the problems in this list sequentially, without undoing each previous step, for which it is crucial to identify the variables that control them and their eventual interdependencies.

One of the first phenomena on the list is "kinematics and dynamics." I am sharing a link to the first video-tutorial in my library in which I give an intuitive view of this topic and take the opportunity to introduce some numerical methods (Finite Differences):
Cinemática y dinámica - Parte 1

You can continue with some "resistance of materials" and its connection with the "theory of linear elasticity". The link to the first tutorial is:
Teoría de la Elasticidad Lineal - parte 1

Then you can see some numerical simulations, from a very intuitive point of view:
Descubriendo las simulaciones numéricas - Parte 1

And some heat transfer in solids and numerical methods:
Calor y métodos numéricos - Parte 1

There are also other simple tutorials on differential equations and other mechanical theory issues (I'm not too interested in making tutorials on CADD+CAE tool handling because there are already too many, and very good ones, on GrabCAD and Youtube).

We can discuss any questions you have. For example, some people find it confusing that "construction and assembly" appears at the top of the list for something that is not actually tested for static, shock, vibration, etc.
It happens that, before making the first static calculation, it is necessary to "give an idea of the construction style" because it can greatly condition the way of verifying the resistance, rigidity and stability. I exemplify this with a bi-supported or cantilever engine crankshaft. In previous steps in the list, the kinematics and dynamics of the "crank rod" system were analyzed with a one-line diagram. But, when dimensioning or verifying its fundamental sections, it is very different if you implement that single-line diagram bi-supported or cantilevered. That is why "certain considerations on construction and assembly" are made very early!