How does one move objects?

[Mr Man]

So I went into a sort of bakery as a zombie had been chasing me. I had closed the door behind me and the zombie decided to start banging on it. I picked up a like wooden shelf with my hammer that contained food which I took out. I then tried to place it down against the door as a barricade but it didn't work. How does this system work?

[Killiberke]

Button on the left side of the screen: pick up ittem.
Click on what you want to grab.
Press R if there are multiple objects occupying the same tile.

When the object is in your inventory, right-click on it and choose 'place'.
Drag with your mouse to rotate.

EDIT: some objects occupy two tiles and become two parts when you try to pick them up. You need both parts before you can put them down again. If your carpentry is too low, you can sometimes destroy one of the parts when trying to pick up the object.