This is a common question in this forum.

Your IB+ is not active, because you haven't earned any points. Buying something on their website, renting a car with Avis, crediting a hotel stay (many partners), Spanish gas stations, etc. If you have SPG points, you can transfer a few to activate your account. However, even after you do this you will have to wait three months until you are eligible to combine your Avios between BAEC and IB+.