The Beat'em Up Engine is only for GMS 2, sorry :(
There's an Starter Kit for beginners available for GMS 1.4 with simpler code but not as much features as the Engine. If you are still interested you can get it from marketplace: https://marketplace.yoyogames.com/assets/7960/beat-em-up-starter-kit Also, I'll publish it to itch.io as soon as I can.