Need For Speed :: San Andreas

Pls help me,im new here and i dont understand how to download this mod for gta,and second question is how to get in to server with SAMP,i tried to put the server ID but nothing hapend

This is MTA server, not SAMP.
Simply download MTA and search for NFS:SA in the browser. Connect and wait till download is finished.

Ok and one more question,can i put this mod in offline san andreas to play in single player?

No, you can't.

How Where Do i download the mod and how to  install it iam new

Just download MTA and copy and paste a IP from nfssa.com or click "JOIN" button.

where do i find mta ? im new