Help with arm CFraming?

First of all, this is not a request for a script, just information.

I am trying to use a script to make a player's arms stay in a specific position after an animation has been played. I have also been doing some research on other Free Models that allow this, but I cannot understand completely how it is done. If you have any advice, somewhere to look for, or just want to guide me personally, please answer/comment to this question.

Any help will be appreciated!

Thank you,

TheArmoredReaper