1. Make sure the game you want to gift is either already on the request list (Link) or you have to first request it. Also make sure the game in question is not already on the retired list which you can find at the very bottom of the requested game's list.
2. If the game is on the request list and has no (!) little parcel icon behind its name you can still gift it.
3. Click on the game's name and find yourself the link in the last paragraph which has "Gift a Game" on top of it.
4. Follow the link, read the disclaimer to gifting a game and make sure you understand what you're committing to.
5. Send the game code to stated email address and wait the mystery to happen.
By the way, there is already a trainer for Battlefield 4 ... Link
[Edited by Taurusplopp, 9/24/2016 12:51:20 PM]
Just click on the link I provided in the last sentence of my previous post or use the "Search" bar in the upper right corner.
But as Battlefield 4 received so many updates by its developers (DICE I presume) you have to have a "Lifetime Membership" to download the trainer.
Don't give up - there is hope
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem