[URGENT] What to do after installing windows on SSD

Software Windows
1

Just bought 240GB SSD - got my 8GB USB ready to install windows on it
my questions:

  1. During the install should i unplug my hard disk ?

  2. Once I (hopefully) install Windows, what should i download next ? - Chrome, and GPU drivers seem logical but anything else ?

  3. Do I need to uninstall steam and re-install onto the SSD to be able to put specific games on the disk ?

At what moment should I be able to plug back HDD ?

Thanks in advance!