Hello, everyone!

Hello, everyone!

I'm new here and I don't know yet how to use ithis website well.

This sounds more natural in the US. You appear to know how to use the site so I edited the sentence to make it mean that you'd like to learn how to use it better.

I'm learning French and I want to practice and improve my English, so I'll try to write here very often!

I'm new here and I don't know yet how to use it.

I would normally say "Langcorrect" or "the website" instead of "it" here.

I'm leaning French and I want to practice and improve my English, so I'll try to write here very often!

I'm new here, so I don't know yet how to use it yet.

I'm learning French, and I want to practice and improve my English, so I'll try to write here very often!