Setup buy full game in game

Hello, this is my first time making games, could someone help me to do the bluePrint to buy the game in its full version, I’ve read the forum and wiki information of unreal, I managed to make the purchase of the game but when I open it again in the cell phone asks me to buy it again

My question is, if I already made the purchase, how do I make the game do not ask me to make the purchase and release the complete game? How do I know that the purchase is made when I close the game and reopen it?