There are 5 basic steps needed to successfully install an Expert Advisor on the MT4:
Open the MT4 platform and select 'File' from the main menu.
Click on 'Open Data Folder' to open a new folder panel.
Select the 'MQL4' folder -> 'Experts' file.
Drag and drop your EA file(s) into this folder.
Restart MetaTrader 4 for your changes to take affect
Note: due to EA's being third party software, and each of them having their own settings, in case of issues activating your EA, you will need to contact your EA provider.