The future tense in German is formed almost identically to the future tense in English. There is a helping verb in German (werden) that functions just like "will" does in English. The only difference is that the action verb goes to the end of the clause. For example, if you meet someone at a nightclub and promise to call her (or him) the next day, you would say, "I'll call you tomorrow!" In German, the verb "to call" is anrufen. (Also, "tomorrow" is morgen.) In German, it would look like this:
Ich werde dich morgen anrufen.
If you talk to someone from Germany who is relatively new to English, she may say things like "I am to the store going," instead of "I'm going to the store." The reason for this is that, in the future tense and all of the perfect tenses, the action verb goes to the end of the clause.
But more about that later. You'll need to memorize the conjugation of werden.
1st person singular (I): ich werde
2nd person singular (you): du wirst
3rd person singular (he, she, it): er wird
1st person plural (we): wir werden
2nd person plural (you all): ihr werdet
3rd person plural (they): sie werden
2nd person formal (you, to an elder or someone in a position of authority): Sie werden
So, to recap -- to write in the future tense, use the correct form of werden as your helping verb, and use the infinitive form, at the end of the clause, for the action verb.