SOLIDWORKS Design & Help

First of all, what kind of bike you want to build,,,?

i would like to decide whether it's use hub motor or geared motor, then decide the power to get the motor size, and pretty obvious battery kind and size.

I suggest you start with the chassis, that way you can have more references for the other parts, I can suggest you work on a multibody piece and direct editing to generate all the configurations of each piece later.

I always prefer starting with the main body. Or the part that does not move at all.

I agree with everyone so far.

Start with the frame.

I'd put the origin at the center of the bottom bracket, but it really does not matter where it is. That just seems like the most logical and useful location.

It's hub motor and Li-ion battery place below the seat

Should I make parts at certain distance from origin where it is to be placed or make part at origin and then at assembly fix their positions?

i will start to get battery size to decide how my frame will looks like, and yes i would reccomend you draw referencing area on origin, altough you can move it later on assembly.

here i place origin on the head tube for easier modification

What you reference above is creating the parts in the main assembly and that includes sub assemblies. Make the parts in separate files. Add them to the assembly through mates. As others have said begin with the frame. You can build the frame on a 3D sketch as a weldment which will make it easier to match tubes and notches.

Thanks all for the help

This is not my video. The right approach in designing. This video can help you.

link