ΒΆ Error-solving and support
While it may be true that CATIA can be quite unstable on lower-end computers, and that sometimes the user interface is obscure and not user friendly, most errors when doing things come from not really knowing what you are doing. Thus, it's very smart to check the User Guide for the particular feature that you are using.
Browsing for the particular feature that you need is usually annoying, as there is a lot of overlapping functionality between the different roles that somebody might have. Thus, instead of using the link it's always best to hover your mouse over the feature that you want and press F1 for help. This will open the User Assistance menu. Clicking on the "More help on this topic" hyperlink at the bottom will take you to the correct User Guide page.
Sometimes, thought, the User Guide does not cut it. So its either that you've made a pretty basic mistake (which is fine, it can happen to anybody), or you've run into a weird error. If such a thing happens, you should look it up on the Knowledge Base. This usually has you covered for all the more obscure errors and features.
It might be that after all of this you can't solve your issue. It is also good to try things in a colleague's computer to see if your instalation/preferences is causing the issue. Asking somebody who has worked on the feature before can also be a great idea, and might save you a lot of time in troubleshooting.