Birmingham public transport

[ChocHotolate]

I am visiting Birmingham next week with my 11yr old. We will be arriving into Birmingham New St and want to go to the Lego Discovery centre. I can see it's about a 15 min walk but with the weather being a bit damp at the moment, it would be useful to be able to get a bus.
Could anyone help me with what bus and bus stop I'd need and how the bus fares work in Birmingham?
Thank you

We would walk that as it's the easiest option & Brum is a great walking city. It looks like the 126 bus goes past it it and around New Street but you'd be on it mainly sitting in traffic and for such a short period of time. In terms of fares, easiest thing to do is to tap on/off with your bank card. You can also download the bus app to buy tickets on there that you scan.

Thank you, happy to walk if that is quicker. In case we do get the bus can I tap twice to pay for my son (in London it's one card = one person)