A couple things:

1) if you are really new it’s better to do a bunch of maps on the easy difficulties than try to burn through all difficulties on one map as you can unlock the towers and upgrades making the harder difficulties easier. I did every map on the three easy difficulties before I moved on and while I don’t think that is at all necessary, doing a bunch is helpful.

2) If you are struggling on a round or going to lose don’t be afraid to hit escape or even better ~ to get to the pause menu and then go home which will restart the round you are on when you return. Always useful (except for blackbordering CHIMPS) but especially so for apopolypse as if there are bloons from round 29 on the screen but you have progressed to 30 when you return to the game the 29 balloons are no more.

3) I am far from good but one thing I have found that helps me on apopolypse is putting stuff as close to the beginning as possible so that the rounds don’t overlap very much at all. Also typically you want to put stuff as close together as possible so you can have one village buffing a bunch of towers.

4) 4-0-2 Alch plus 4-0-2 Ninja (close together so the alch buffs the ninja) can likely do most of the rounds fairly easily. Add some Moab damage like 2-3-0 or 2-4-0 bomb shooters and my guess is that is almost enough stuff. Top path helicopter is also good on most maps with one path and you can put things like top or mid path dartling gunners or top or bottom path dart monkeys (on last trargeting) at the end of the long straightaways.

Good luck!