I have a question about my toilet?

This is most likely a silly simple question but we have had some plumbing problems since we moved into this house in August. The toilet has overflowed all over the bathroom on two seperate occassions so I’m veryyyyy weary at the slightest problem.

Anyhow: I noticed the toilet was running tonight. I didn’t know what to do….so I left…came back about an hour ago and it was still running so I fiddled with that little wheel near the floor and turned it clockwise til the water stopped running. So…now it’s quiet but what happens when I flush it now? Should I turn the knob back to where it was?