If windows 10 is registered to your account, you should have no problems transferring your license.
As a check, list all of your parts.
If you have already ordered, there is not much that can be done if there are better options.
I assume that you are starting anew and not hoping to keep any installed apps.
Install only your new ssd and install windows on that.
Leave your old HDD disconnected during the process.
You can reattach it later and do what you will with it.
Your files will still be accessible, but apps will need to be reinstalled.
If you hope to retain your current environment, that is another different and more difficult thing.
MY build process:
Before anything, while waiting for your parts to be delivered, download
and read, cover to cover your case and motherboard manual.
Buy a #2 magnetic tip philips screwdriver.
I find it handy to buy a power switch like this for testing.
https://www.ebay.com/p/4in1-PC-Power-Reset-Switch-HDD-Motherboar-LED-Cable-Light-Wire-Kit-for-Computer/631889283?iid=142232821294&chn=ps
1. I assemble the critical parts outside of the case.
That lets me test them for functionality easily.
A wood table or cardboard is fine.
2. Plug in only the necessary parts at first. Ram, cpu, cooler, psu.
Do not force anything. Parts fit only one way.
Attach a monitor to the integrated motherboard adapter if you have one, otherwise to the graphics card.
3. If your motherboard does not have a PWR button, momentarily touch the two pwr front panel pins with a flat blade screwdriver.
4. Repeatedly hit F2 or DEL, and that should get you into the bios display.
5. Boot from a cd or usb stick with memtest86 on it. memtest will exercise your ram and cpu functionality.
6. Install windows.
7. Install the motherboard cd drivers. Particularly the lan drivers so you can access the internet.
Do not select the easy install option, or you will get a bunch of utilities and trialware that you don't want. Drivers only.
7. Connect to the internet and install an antivirus program. Microsoft security essentials is free, easy, and unobtrusive.
8. Install your graphics card and driver if you tested with integrated graphics.
You will need to remove the graphics card later to install your motherboard in the case.
Make a note of how the graphics card latches into the pcie slot.
The mechanism will be hidden under the card and may be difficult to work if you have not previously checked how.
9. Update windows to currency.
10. Only now do I take apart what I need to and install it in the case.
11. Now is the time to reinstall your graphics card.