Advice on correct guide to follow? Currently running Mojave and want to create a new partition for windows 10

Extreme noob, but I want to create a new bootable partition for windows AFTER all of my initial setup. I would like to use the same ssd drive, but I’m so scared I’ll break my system. I can’t figure out which guide to follow, so please can anyone help a noob out and point me in the right direction?