Creating a TD aid

Well, I'm working on a TD and I'm gonna begin making waypoints now, but the thing is taht I'm not so very experiensed with making triggers, so I wondered if anyone could help me out with this?

For your infomation: the TD will have 8 players, 17 towers each builder/race, I'm not sure how many lvls its gonna be.

I need a guide in making waypoints triggers, that creep system, with lives and such.

On each corner of the map on start of each level its gonna be a ship loading off creeps to the shore and from there the creeps begin to move to the center through the maze.

Also if you know how to make tower to auto cast a attacking spell without using manual clicking, like shockwave for example.