Installing CRUX on 2nd HDD

Dear CRUXers, I need your advice before I proceed with a new installation of CRUX 2.3 I have an older CRUX on /dev/sda, under which I'm currently working. Then I have a second HDD, which can be mounted using USB cable as /dev/sdb. How can I install CRUX2.3 on /dev/sdb (through USB cable), working under /dev/sda at the same time? I imagine I should chroot to CRUX2.3 install CD, and then proceed as in a normal installation. By I'm not sure how to properly chroot to CD. Can you give me any hints? I cannot attach both HDD's at the same time as IDE devices - it's a notebook. Also it's too simple to exchange HDD's for installation :) I appreciate any help, Pawel