Today

"Suddenly I was home." This would sound more natural as "Before I knew it I was home."

I rephrased the last sentence to better express what I think you were trying to say. My apology if I was not correct in understanding you. 

Today

I went to my German class in the morning, and what did I learn?
There are 2 independent clauses ("I went ... the morning" and "what did I learn", and there are about 3 easy ways of avoiding the comma splice (and 2 easy ones for connecting independent clauses)).
1. Put a period between "morning" and "what" to create 2 sentences.
2. Use a coordinating conjunction (FANBOYS) to connect the 2 independent clauses into 1 sentence. In this case, "and" fits the sentence, but you still need to put a comma before "and" since there are 2 independent clauses.
3. Use a semicolon to show that the 2 independent clauses are closely related to each other (and forming 1 sentence with 2 independent clauses).
"I went to my German class in the morning; what did I learn?"
There are more punctuation methods, and I think these 3 are the easiest ones to learn.

I learned how to give directions to people and how to say the time.
Removing the second "how" is optional. The reason why this "how" can be removed is because "how to give directions to people" and "how to say the time" tell us more about "I learned".
"I learned how (1) to give directions to people and (2) to say the time."

When my class finished, I went to the bus station.

There was a lot of people!
Subject-verb agreement. In this case, the verb "to be" needs to agree with the subject "a lot of people".
"There were a lot of people!"

The good thing was that I had someone to talk to, so the time felt fast.
You always "talk to/with (someone/something)".
"I talked her"
"I talked to/with her

Suddenly, I was in home, and I started to do all my homework, waiting to finish someday :c
- The adverb "suddenly" is used here as a sentence adverb (it modifies the entire clause/sentence), so it should have a comma.
- When you say "I am home" it is implied that you are inside so saying "in home" is wrong; however, you can hyphenate them together to "in-home", and it turns into an adjective that means "happening in one's home".
- The second comma is added to separate the 2 independent clauses (same principle as stated above).
- I like how you properly punctuated the participle phrase "waiting to finish someday" that acts as an adjective modifying "I"

I enjoyed reading your entry ^^