Instructions
Download the latest version of the ENB series for "Grand Theft Auto: San Andreas" from the GameFront website. Once the download is complete, you will have a small zip file.
Right click on the downloaded file and select "Extract All" from the pop-up menu.
Click the "Browse" button when asked to select a destination for the extracted files. Specify the folder on your hard drive where your copy of "Grand Theft Auto: San Andreas" is located. For example, if you installed the game to the default location, you will specify in "C:\Program Files\Rockstar Games\GTA San Andreas"
Click the checkbox next to "Show extracted files when complete" and click the "Extract" button.
Start Grand Theft Auto and hold down the "Shift" button and press "F12" to finalize the install and activate the mod. Don't be alarmed if the game stops responding for a few seconds while the mod loads. This is normal.