we use commas to indicate short pause before the main clause

Two example is correct

commas are used to indicate short pauses on sentenses

Nice

it's indicate to short pause in writing.

done

thank for sharing knowledge.

In example one exactly I didn't understand meaning of these sentense. In second example we do understand how is important using comma.

In example first I read sentese ,but even i didn't breathe,so I understood it was mistake. The didn't use punctuation.

Once again... It makes the text much cleaerer and easier to understand