If I do a clean install of Windows 10 to a new SSD and have additional hard drives, will I have to reinstall/format the info on them?

I got a new SSD and want to put my OS on it. The consensus seems to be to unplug everything but the SSD then put a boot disk in, and install Windows from there then plug everything in.

My question is, I have a few other HDDs in my computer with backups and stuff on it is rather not fear over to an external. Will I need to reinstall those extra hard drives thus having to format them? Or when I reconnect them will they be accessible from my new clean install Windows on the SSD?