Unity + Android- app from "Unknown Source"

I haven’t been able to figure this out yet- I’m working on a game and creating apks, but every time I want to test my apk, my Android phone tells me it’s from an unknown source and I have to allow the installation of apps from unknown sources on my phone.

My app is signed, but I don’t know how to get past this unknown source issue.

Thanks!

You need to enable a security settings

See:
User Opt-In for Apps from Unknown Sources