I was trying to find a website where I could post my thoughts and ideas and others canould help me.

You want to use the conditional “could” both times in this sentence.

I have ptroublem trying to connect the sentences and. I do non’t need to learn how to write perfectly, but I would like to learn native ways to express myself more like a native speaker.

In place of “I have problem trying “, you could say “I have difficulty” or “I have problems” or “I have trouble”, but you wouldn’t use the singular “problem”. I split your sentence into two for stylistic clarity. “learn native ways” sounds unnatural in this context, I provided an alternative which will be understood more clearly.

However any correction it is welcome.

You don’t need the “it” in this sentence.

He shared it, and I thought it was exactly what I was looking for.

Use a comma in combination with "and" to separate two independent clauses. This site goes into some more detail: https://lifehacker.com/remember-the-fanboys-rule-for-proper-comma-usage-1755944556

I have problemdifficulty trying to connect the sentences, and I do not need to learn how to write perfectly, but I would like to learn native ways to express myself.

I would try to avoid combining 3 or more sentences using conjunctions. It's easier to read when you split them up in separate sentences. I would rewrite the sentence like this:

"I have difficulty trying to connect the sentences. However, I do not need to learn how to write perfectly, but I would like to learn native ways to express myself."

My personal goal is to learn how to write better, find new vocabulary, and correct my grammar.

A comma is generally after everything in a list before the final "and".

I have problems trying to connect the sentences and I do not need to learn how to write perfectly, but I would like to learn native ways to express myself.

However, any correction it is welcome.