Assuming you have GTA SA and SA:MP installed, now you need to add our server to your favourites.
1) Open your SA:MP browser
2) Click on Servers -> Add Server
3) Copy and paste our IP address (149.202.42.25:7777) and press OK.
4) Double-click on SFSE and Connect.
You should be able to play now if your GTA SA and SA:MP are installed correctly.