Back on the dating scene

Hey everyone! So I've been single for almost 2 years. Recently I've been talking to a few different guys, some met through dating apps, others through friends... here's my question.... what's the rule for casual dating? Are you expected to tell them you're dating other people or is that just not addressed unless someone wants to have a committed relationship? I should clarify there is no sex involved at this point. I just am enjoying getting to know people, and having a good time.