The two issues you reported are not related. The first is to get the extension to be recognized by the PBX so that it can make and take calls. The second has more to do with a directory.
You need to solve the first issue (registration) before moving to the second.
As you gave no information at all about the phone type, the PBX version, etc. The best I can suggest is to use the blog from above and enter a search term for phone registration. There is also the manual, but the blog is more descriptive.
Recordings are stored in the server. Look in the Program Data folder (hidden, so you will need to unhide) and then the 3CX folder. There will be other folders of which one will hold the recordings. I do not recall off-hand,, but if you look around, you will find them.