Next bids. Finding the level
First agree the suit
After the first few bids, you should now know if you have a suit with an 8-card fit. If so, then confirm this to your partner either by passing (if that was the last suit bid and assuming you don't wish to go any higher), or by bidding if it was not the last suit bid.
Sometimes you will have to accept the best 7-card fit that you can find.
Alternatively, if you have stoppers in all 4 suits, you can select No Trumps.
At what level
Let's suppose you've agreed the suit. How do you decide when to stop bidding ? At what level ?
If you are bidding in competition with the enemy for a contract, you will often be prepared to bid a bit higher than usual, and risk going down the odd trick, if the penalty for going down is less than the enemy will make from their contract. You need to think about "vulnerability" when making this calculation.
If you are not in competition (because the opposition have stopped bidding), then the main consideration is whether you and your partner have enough strength for game or slam, which you can read about on other pages. If you do not have enough strength, there is little point in raising the bidding any further, assuming you have agreed the suit: all you do by bidding higher is to increase the chance of failing to make the contract.
In very broad terms you need about 25 points to make a contract of a bid for 4 suit tricks (that would be game if it's in a major suit), and an extra 3 points for every extra trick beyond that (5 tricks needed for a game in a minor).
There are various other techniques for helping to decide whether to go for game, which are probably beyond the scope of a beginner. The most useful one is the Losing Trick Count.