It is a random tower that pops up. I think you have to wait, till one appears. As of right now, it is where tower "Challenge 269 " is right now. Keep in mind, there are 2 types of team towers. Two players vs CPU and 3 players vs CPU. The 3 vs is the one with the trophy/ achievement.

I know how to make. but im playing in 4 days in a row and dont see any of this towers

I saw quite a few of these pop up shortly after launch. I finally did one about two weeks ago. Went great...I did about 75% of the work before I died. Could've done without the obnoxious turd on his microphone making orgasm noises. I hate other gamers, lol.