You could also play on turbowarp for better quality.
https://turbowarp.org/565877149?limitless&offscreen&clones=Infinity&fps=60
The menu on the right is the tower menu. where all towers are located. Select one if you can afford it and place it anywhere on the map. After placing it, you are able to click it to open it's upgrade menu. Upgrades are used to maximize your tower's power, each path with it's own unique gimmick! When upgrading past tier 2, other paths will be unable to upgrade past tier 2 and when cross-pathing, only 2 paths can be crossed and the other will be restricted. that's how bloons works