Find and replace line breaks

Hi, new onlyoffice user here.

I'm formatting whisper transcriptions and would like to find and replace all line breaks which are very time-consumming to get rid off manually.

There identified as ^ p (without the space), but when I try to replace them with a space it just adds it at the end of the line and doesn't fix my issue at all.

Does anybody know how to do this ?

Thank you !