I would also recommend plenty padding. Higher up the leg it can be harder to stop any movement in the fracture, but bandage as high as you can, and get the splint up the side to include shoulder if you can, sometimes wrapping all the way round the body to secure that high, making sure not to restrict breathing. Signs to look out for include swelling, particularly round the top of the bandage, cold feet under the bandage, discharge of any kind and amount, any bad smells. Bandages, particularly for broken legs can cause really nasty sores, or even gangrene, so if you see any of these signs, i would take it straight to the vet who can treat it. I tend to leave casts on growing animals for about two weeks at a time, so you can change it as they grow, but bone healing often takes about 6 weeks or more. It should be able to walk on the splint, if not, you may need to go to your vet as they may be able to put on a plaster or a more specialised, shaped leg splint.
Good luck
Suzanne