Present tense is for the present time; that is the now.
I eat apples. John plays baseball. We learn spanish.

Preterite is past tense what happened and ended in the past. Matter of factly, less descriptive.
I ate apples. John played baseball. We learned spanish. He was wounded in the battle.

Imperfect is another past tense, but it is what was in the process of happening when something else happened (preterite). More of a descriptive past tense.
I was eating apples when he called. John was playing baseball... We were learning spanish...
It also can mean "to used to do."
I used to eat apples.  John used to play baseball. We used to learn spanish.

Future is what will happen.
I will eat apples.  John will play baseball.  We will learn spanish.

Conditional is what would happen if a condition was met. Frequently used with "if."
I would eat apples. John would play baseball. We would learn spanish.

Commands is a command form; telling somene to do something.
Eat apples! Play baseball! Learn spanish!

Present Perfect is what you have or haven't already done.
I have eaten apples. John has played baseball. We have learned spanish.

Plu(or past) Perfect is what you had done already in the the past.
I had eaten apples. John had played baseball. We had learned spanish.

Subjunctive is used to convey a wish, and express mood and doubt. Almost non-existent in english.
I wish that you stop smoking. I doubt that you can come. I hope you learn spanish.

Remember in spanish to form these tenses, you just add different endings to the verb.
(They don't use the word "will" to speak in future tense.)