Before playing GTA SA-MP, you need to install the Need 4 Dare V.2.1 (SAMP). The installation is quite simple, just 2 clicks and you're done. Furthermore, you even don't need to backup your files, the installer* is advanced and take care of backup itself. If you need to uninstall the map mod then all you need to do is install the backup that can be found in game directory after the installation.
However, you must make sure that your GTA SA is clean (if only SAMP installed, it doesn't matter).
If you done the installation, add the following IP in samp fav list.
Server IP : 74.213.178.155:7777 Server down, will be up soon
*Its X Mod Installer V.1.5.1 Xtreme, can be found here.