The enb series mod consists of a single .dir or .bin file in the game's root folder IIRC, I don't think you'd need SAMI at all for that.
It's a .dll, either way, quote from readme:
So yeah, download and of the enb series mods for SA off the official site, and move everything that came in the folder into wherever your San Andreas exe is (NOT the shortcut)
Then when you go ingame, note some text in the upper left corner. Hit shift+F12 to activate it, it'll be obvious in the menus as well as ingame.