Plans and Changes

I had a wonderful weekend last week.

This is grammatically correct, but you can make it more clear by saying:

- I just had a wonderful weekend.

or

- I had a wonderful time this past weekend.

I took a few videos and pictures and planned to share them with you guys because I noticed that those videos allowed me to practice more detailed English expressionsdescribing things in English in more detail.

And I can't upload them tonight too since I would be very late at hom'll be getting home late.

I had a wonderful weekendtime last weekend.

Your original sentence doesn’t work in US English because I’m not certain which weekend you’re referring to. This is probably related to the fact that our calendar begins on Sunday and ends on Saturday, so each week has two “weekends” (Sunday at one end and Saturday at the other). That said, I can tell that you must be referring to the most recent weekend. :-)

A couple of alternatives to my correction above:
• Last weekend was wonderful.
• I had a wonderful weekend. (We assume you’re referring to the most recent one, so “last” can be omitted.)

I went on a hike on Saturday and met with my two classmates on Sunday.

“My two classmates” would be correct if you had already told us which two you meant, or if you only had a total of two classmates. As another corrector indicated, “met with two of my classmates” would also be idiomatic.

I took a few videos and pictures and planned to share them with you guys because I noticed that those videos allowed me to practice (using) more [detailed] English expressions.

“Detailed expressions” isn’t right, but I’m not sure what to say instead. Maybe, “…allow me to practice expressing myself in greater detail.”

I planned to upload them last night, but I was too tired after a meeting at 7:30 pm / after a 7:30 pm meeting.

And I can't upload them tonight tooeither since I would bill get home very late at home.

If I can get up 30 minutes earliery tomorrow morning, I'll do it then.

Oddly enough, without “then,” “I’ll do it” seems to mean “I’ll get up,” but with “then,” it means “I’ll upload the videos then.” English is weird sometimes. Ok, maybe it’s weird most of the time…. ;-)

I went on a hike on Saturday and met with my two classmates on Sunday.

“two of my classmates” sounds more natural in casual, conversational English.

I took a few videos and pictures and planned to share them with you guys because I noticed that thoese videos allowed me towould help me practice more detailed English expressions.

The word "those" refers to something farther away in time or space, while "these" refers to something closer to the speaker. Since you're talking about videos you just took, "these" is the more appropriate choice.
"Would help" sounds more natural here because you're explaining a potential outcome or benefit of sharing the videos

However, I can't share them with you right now because I haven't uploaded them yet.

"Right now" is a more precise way of saying "at this moment" or "immediately."

And I can't upload them tonight too since I would’ll be very late atgetting home.

"I’ll be" (future tense) fits better.
"getting home" sounds more natural than saying "at home" because the action is about arriving home, not just being home.

Then, I'll find time to share a video with you tomorrow at noon.

Commas help break up ideas into smaller chunks, making the sentence easier to understand and read. In longer sentences with multiple parts, commas ensure the reader doesn't get lost in the meaning. The comma after "Then" separates the introductory word from the main idea of the sentence.