My tirp to a wetland park

My trip to a wetland park

Not sure but it definitely doesn't sound right... Maybe you don't need "wetland".

I want to share my experience, of having an outdoor activity last Saturday.

It was really impressive and very interesting.

Do note past tense.

We have finished some tasks working in groups.

Although you say "working in groups", the task you finished was just "in groups". Not very sure how to explain it...

We rented a special bicycle which can carry 4 people each at a time to walk cycle around the park.

Remember past tense. "at a time" refers to "same time". "cycle" is the verb used to move on a bike.

We even made a our own kite, it was very difficult and it didn't last fly up to in the sky longat .

You made your "own kite". This is the correct grammatical structure.
Remember past tense.
This one is a bit fiddly but you can say that it "didn't last in the sky long" to say that it didn't fly very much.

These are all precious memories to me, which I hope I have can shared this with you!

You need to tell us who you're talking about.
Not sure what to do with this but it gives the meaning that that says "I have shared it with you".