English doesn't have a future tense, so it makes use of modals (will, may, might...), idioms (be going to, be about to...), present tenses (present progressive, simple present) and verbs like and plan and intend to talk about future time.
Like all modals, will is followed by the simple (root) form of the verb:
The semester will end on April 29.
To make a negative, add not after the modal:
There will not be any classes after April 24.
(Contraction: will + not --> won't)
To make a question, reverse the subject and modal:
Will you go back to your country in the summer?
We use will to make predictions about the future and to express spontaneous (unplanned) decisions.
Example of a prediction:
The economic crisis will last for a long time.
Example of a spontaneous decision:
I'll help you with your homework.
To review, watch Paul's explanation of the "simple future using will".