u/L0rd_me

Beginner here so you'll probably come at me. Ignore all copper pipe work and electrics as this isn't the corner it's going in however does work the same. Blue is shower waste and yellow will be from the sink. I want the green circle to be a hole in the wall which will lead to the drainage outside. How can these connect as I can't understand how to use a Y connection in the corner of the room and still having all flow nicely out. Thanks!