There's a population menu where you can hire people, which is how you bring them in. I will admit the gameplay is a bit janky though; the project was probably a bit ambitious given the deadline. In any case, the crashing bug should be fixed now - it was missed during testing since it only affected the Windows build (something that should not have worked in the Linux version worked anyway), and my Windows computer that it should have been tested on was experiencing technical issues at the time.