In reply to Chloe:
If you're unsure on how to belay a second up, are you sure of the skills needed to bail off a multi-pitch sport climb or abseil down it after a successful ascent?
If you're using a regular belay plate, attach yourself to the anchors using an appropriate method, and belay like normal. Preferably aligning the rope so it comes from the climber up in to the bottom of the plate, and the rope to your brake hand comes out the top of the plate. If you've not done this before there is a lot less friction in the system so holding a heavy/falling second is harder, so make sure you're able to lock the plate off adequately!
Belaying in guide mode definitely makes things easier for you, but do you know how to release a weighted plate in guide mode safely?
Stick to what's safe, simple and what you know!
Post edited at 15:55