I currently have a desktop computer here at home which I use for work.
I've just purchased a laptop, and it will be sharing my ISP connection.

In order to keep things pretty orderly, I would like to have a different
account for mail, downloads, etc. just for the laptop. I think all that
means is, I use the same ISP account with both computers, but a different
email account within this ISP account, (and password) for the laptop is what
should keep things straight between the two machines. (?) If this isn't the
whole principle, then I need to know that.

Where is the best place to go and get instructions for setting this up (it
should be clear instructions for a non-techie) including what to do first,
etc. Thank you.