I had this machine for 2 years now and it came with a 256 Gb SSD Toshiba drive + 1 TB HDD

I started to run out of space so I bought a 1 TB 2280 nvme SSD which will come to me in like a week.

Could anyone help me with the procedure I need to use to get a freshly installed Windows on the NEW SSD? I mean - I have already created a bootable USB through Microsoft tool that I am going to use, so the question now is how to get the new drive to be the one that's used for booting automatically and not the old one (I would rather keep everything that already is on the old 256 Gb one and not format it). Should I unplug the old SSD before I start Windows installation? Should I fiddle with some settings in BIOS?

What about Windows key/activation? I guess that's taken care of by UEFI or whatever it is called?