Dell G3 3579 OS Installation on new SSD

Your best bet is to Clone your old SSD/Hard drive to your New SSD. This is a very simple operation will take you about 20 minutes or so and you won't lose anything.

First, ensure that your notebook will accept a 970 Evo M.2 NVME 2280 Card?

Download and install Macrium Reflect Free https://www.macrium.com/reflectfree

If you have 2 M.2 NVME slots very easy just install the 970 alongside the old SSD, Boot up using your MR recovery USB Thumb Drive

Once in the MR environment"Windows PE" set up the Clone, drag each partition from your old SSD to your new SSD expand your C: partition to fill up the empty space on your new SSD you are going larger correct? https://www.youtube.com/watch?v=LClr3FPg4_4

Run the Clone, when it finishes shut down and remove your old SSD. Not boot up and you'll be right where you were only on your new SSD.  https://www.tenforums.com/tutorials/61026-backup-restore-macrium-reflect.html

If you want to use your old SSD you'll need to acquire a USB to M.2 NVME adapter or external case. Connect it VIA USB and format it as a Logical drive then you can reinstall it back ion your notebook as a 2nd drive. https://www.amazon.com/s?k=usb+to+m.2+nvme+adapter&crid=NBY8SQ84M8PE&sprefix=USB+to+M.2+NVME%2Caps%2C147&ref=nb_sb_ss_i_1_15

If you're not going to reinstall it the save it aside for the future. Should you want to seel your notebook you could remove your new SSD and put the old one back in then run the Dell Recovery so whomever you sell it to will have a fresh OS they can set up for themselves and all your data will not go out of your hands.