In laptops is the same procedure than in general PCs. To add an EA, open MT4 and then go to 'file' and then 'open data folder'. Choose 'MQL4', and then 'expert advisors' or 'indicators'. You can then copy the file you want to add into this location. Close and reopen MT4, and you should see the item in the navigator window. Lastly attach the EA to a graph and magic in the form of automatic trading occurs.
I do not know the procedure for mobile phones.