how to make a gear in CATIA V5?
3 Answers

there is no basic step for gears in catia. all complicated.
Check this: http://www.edstechnologies.com/training/DESIGNING-GEAR-IN-CATIA-V5.pdf

please see this CATIA app
http://spadantechnic.com/en/articles/catia/catia-app-for-gears-and-sprocket-and-bearings.html
you can download free app for gears in this site