Just copy the part where you want to reply to and type > after paste the content press on enter and please make sure you leave a free line and start typing .

Hi, I just want to ask how to show the comment of an author and put it into another comments like a quoted one? Something like this ?

I got it

You don't have to copy and paste someone else comments for your comments. You can only copy a part of a comment you want to reply. Just paste it on the reply section, leave a space and type your reply.