okay, so in order:
1) this is the menu button. typical pause-type game menu. has options, lets you return to the main menu, that kind of stuff
2) this is the main game board. don't worry too much about how the gameplay works (partly because there's different modes that change it a fair bit). the key thing to know is you place tiles, and the placement of those tiles is restricted to neighboring tiles with certain properties. a tile A might be able to border tile B, but tile C might not.
3) this are the three tiles you can choose from to place. when you place a tile, a new one takes its place from your "stack"
4) this represents your stack. the "+72" means there are 72 tiles left in your stack
5) this is your score. the small number with the star is your high score for this mode