SS Express - grant other users access

I am a BI person so I can use a DB, but setting up and configuring - not so much (last time I created a DB was DB2 UDB on NT). I'm learning but looking for aquick start if anyone can help:

I have SS 2017 Express installed on a machine on my network. I need to grant other users on the same domain access to this instance. What is the quickest way to configure this?

Thanks.