How to add internal HDD to newly installed Windows without formatting?

My computer has become problematic so I’ve decided to reinstall Windows 7. But before I do, I just want to know if I will be able to add and access my secondary internal SATA HDDs without having to format them. I’ve seen in a YouTube video that they initialized the HDD and then when it came to the New Simple Volume Wizard, after assigning a drive letter, the dialog box said “to store data on this partition, you must format it first.” Does that mean I won’t be able to use my hdds (read/write) without having to format it first?

If it's a brand new drive they have to have a partition created then formatted. If it's a used drive it should be ok as it is

It is a used drive that contains my media files. So I just have to plug it to a SATA port and I will be able to access it or do I have to initialize? I mean what’s the procedure? Sorry, I just want to know if I’d have to back it up first if formatting is needed.

To install or reinstall win 7 make sure ALL other drives are disconnected from MoBo (power or SATA cable).
Once you finish installation with all drivers and updates installed, shutdown and connect the other HDD to the MoBo. You don't need to do anything to the disk.
Clean Install Windows 7

Ok thank you so much!