Ok. You need to actually click the Quote button and copy the text from there and paste. I suggest you save it all in a notepad or something incase they are removed from your signature. That's pretty much all you do.
Oh, btw, I did mention they might be removed from your signature to make this clearer: put your vouches in your profile. That's the only place they are allowed. But when you get a ton of vouches that will not all fit in your profile I suggest you use an old, old thread of yours that is in the archive (preferably a thread in the market) and edit the first post of the thread to paste all of your vouches there.
Thanks I did copy the post but there is supposed to be a little sign next to the name of the voucher that looks like " > ", that is a link to the thread that the vouch was posted on
then try it again go back to the original post, press quote, select all, CTRL + C and CTRL + V in your signature and then delete system32 in your C: drive (kidding lol)