i have finished kh3d and one of the trophys is to place a certain amount of link portals but i'm not shore how.

The pink button on the touch screen.

^ That

And you need someone with the same game to take the portals before you recall them.

I was told them them for a period of time would do, but I've done this with 12 spirits 4 days ago and they still haven't been used by the game.

same i put down a few and they still haven't been used but i see other peoples around and i use them but mine just sit there and i don't know anyone who has the game so i can't get the trophy.