Letters of recommendation

Hello. I am planning on applying to graduate school in spring and they require three letters of recommendation (two academic, one non academic like an employer) which are basically a form to fill out.

What is the protocol? Do I have to know them really well?

How many classes should I have taken with them?

I don’t know the professors in the psych department at my university the way I knew the psych professors at my CC. Can I get a recommendation from one at my CC and two from the university? Do they all have to be psych professors?

My university is a CSU and not far from the CSU where I am planning to apply for the masters program. Any advice would be welcome. Thanks.

I should add that I am an older non traditional student who hasn’t done internships because I have a full time job and combined with school there’s just not enough time in my schedule for it.