English’s future tense

There are various future tenses.

Future Simple / Simple Future: Will + [base form] -- I'll eat that later; or Going + [infinitive] -- I'm going to eat that later.

Future Continuous: Will be + [present participle] -- I'll be eating that later.

Future Perfect: Will have + [past participle] -- I'll have eaten that later.

Future Perfect Continuous: Will have been + [present participle] -- I'll have been eating that later.

There's also using the present continuous to talk about the future -- I'm eating that tomorrow.

Also, the simple present -- I eat that tomorrow.

English is flexible, but it's also weird. There are a lot of distinctions that matter to native English speakers but that are really hard to put into rules. Like "will" vs. "going to". They have slightly different meanings, but good luck coming up with an easy to understand rule about when to use each version.