I went to the main area on the ground floor and asked to join. They don't have a big enquiry desk but have roaming staff and a pod of staff computers and a small desk. The staff are very helpful and the assistant said it would be quickest if I went downstairs to the bottom floor. This seems to be the Scottish floor with Scottish related books and stuff. Anyhow there was an interesting conversation going on between the assistants and a man who had lost his book 'in the drink'. I asked for a card to join and was given one - the assistant was a bit suspicious of me at first but thawed out gradually and explained everything I could do with my library card and how to get ebooks or access computers or the Internet.
I went back upstairs and resisted the temptation to get lots of books. I chose two and used the self issue machine which worked well.
I'll explore the building more next time. There was a display of some tiles on the staircase. I liked the look of them but can't remember what they were.