Future tenses

He is (not) going to start a course of Spanish in June 

I                         +   am
He/ She/  It        +   is            + going to    + infinitive
We/ You/ They  +   are

Uses: Plans, intentions which we have already decided to do in the future, predictions with evidence.

He will/ won't start a course of Spanish

Pronoun+ will/won't + infinitive

Uses: General predictions about the future, objective truth in the future, when we decide to do something.

Present continuous: He is starting a course of Spanish

I                         +   am
He/ She/  It        +   is            + gerund
We/ You/ They  +   are

Uses: More sure and casual that going to + infinitive. 

Present simple: He starts a course of Spanish  in June

Uses: When an action is part of a timetable or a routine. After a time expression such as: as soon as, until, after, when and before.

Future continuous: He will be studying a course of Spanish

Pron + will/won't + be + gerund

Uses: Activities in progress at a particular time in the future 

When my husband arrives home, I will be finishing my marking (correcting)

In May I will have been studying Spanish for one year.

Future perfect: He will have studied a course of Spanish

Pron+ will/won't + have+ past participle

Uses: To talk about activities what will be finished at a certain time in the future/ Often used with "by" (By the time this time has finished, I will...). or "at" (At 16.00h, I will have been there for 8 hours).