Please, somebody help me. I have managed to click on my Documents folder and unfortunately, they've gone into the trash can next to them. I can't get them out again. How do I do it?

A am sorry to hear of your loss.

Click on the Desktop and do Command+n a New Finder Window should open. On the left do you see a folder named Documents? If so, select it - is it empty? If so, leave the Documents window open and then open the Trash where hopefully you can see all the files you want to recover? Select one file and then do Command+a to 'select all' and then drag them to the open Documents folder and release. The files should now be back where you need them. With the Documents item in the left side panel of the Finder window selected, click and drag it to the Dock and position it to the left of the Trash can, a space should open to accommodate it. Let go and your Documents icon should be back in place.

I was just trying to move the documents from one side of the trash can to the other

That is something that won't work - the trash can is, by default, the last item on the right in the dock. Everything else has to be to the left of the trash can.

Open the trash, select the files and then select 'Put Back'