I want to chnage the game background and to add some more features.

hi i have a xcode game project it's completed but i want to add more item to the game and the admob banner is not working as it's intend to and i want to fix that and add admob interstitial to the game as well. It's flappy bird game project at the moment the game has only 1 bird and 1 background the daytime one so i just want to add more birds so every time you restart the game it should be different colour bird with different background day and night cycle basically I want my template to play and look like real flappy bird and update AdMob banner and add AdMob interstitial so when you restart the game 3 times the AdMob interstitial comes up in the game over screen. Please let me know about this thanks.