Catia Users

Hi bojana there is a lot of tutorials about making gear on catia v5 just tape gear in catia v5 in the search bar and you will find a lot of tutorials about it

good luck in your studies

Things like center lines and pitch circles can be added to the drawing views after the gear is projected into the view.  Dimensions and notes too.

Just draw directly in the view.  You don't need a sketch in the drawing; the drafting tools will work very similar to  the sketch tools.