Need help with punctuation...

Need help with punctuation rules please

The obvious one is:
end every sentence with a full stop or equivalent mark.

Rule to use of comma before or after a conjunction please

Ut depends on the sentence, there is not a specific single rule which you can follow.

Thank you.
She is a lovely lady with a lot of compassion and a great ability to work with the elders.

It’s this sentence correct?
Tx

That is okay as it is. Some people might choose to include a comma after ‘lady’. That is fine too.

Tx you. What about a coma before and.

It wouldn’t usually be required there.

Tx is not a word. You mean ‘thank’.
Note the spelling of ‘comma’.