How do you journalize a payment made by a check e.g paid Dec rent with chack #12221 for $500? And a check received on account of $1000?

Cash is a debit account, meaning increases are debits and decreases are credits. But the other side of that entry depends upon what you are paying or where you're receiving it from. In the case of rent, it's debited to rent expense, but checks are written for zillions of different things so they'll all be different entries.