We use the first conditional to talk about future actions that can only happen when a certain condition is fulfilled. This condition is told in the if-clause.
That means we use the 1st conditional for:
future consequences - If I start a part-time job, I will earn my own money.
warnings and threats - If you do that, I won't talk to you ever again!
negotiations - If you do my chores today, I will do yours tomorrow.
How to form the 1st conditional:
Use the present tense in the if-sentence and will/won't or the imperative in the main sentence. The sentence can either start with the if-sentence or finish with it. For example: I will do your chores tomorrow if you do mine today OR If you do my chores today, I will do yours tomorrow.