Finding files by text inside them

[m^2]

Hello,

I'm trying to find custom files but I cannot get to understand how Find Files dialogue box works. Post me please, some examples of what to to fill where or which box should be checked.

The basic stuff is simple: You fill only the "Search for" field and leave the rest default.
If you need more, when in the dialog box, press F1. You'll find some examples there.
If you'll have troubles with it, please specify what do you want to find and we'll try to help you.