Puppy Pees on His Bed?

I have recently adopted a 5 month old Staghound x Lab puppy. He is very nervy and is not house trained, but he seems to wee wherever he feels most comfortable. This is in places like under the table or on his own bed! I will take him out for walks and then we come home and he pees straight away, but it's always inside! At night though he only pees on his bed, not anywhere else. I don't know how to make him stop without making him not like his bed!