If you have only the cpu and gpu, start there.
The motherboard you listed supports only 8th and 9th gen processors.
I3-7100 will use a 200 series motherboard.
Yes, the case does include a 500w psu, but I would be hesitant to buy a cheap psu. The quality of Coolermaster can be iffy and a cheap psu can damage other parts if it fails under load.
At $39 on a strict budget, you could take a chance.
Make that 8gb of ram a 2 x 4gb kit to get dual channel operation.
I will never again build without a ssd for the "C" drive. It makes everything you do much quicker.
120gb is minimum, it will hold the os and a handful of games.
But, many things default to the "C" drive.
When a SSD nears full, it will lose performance and endurance.
240gb is the recommended minimum.
If you can go 240gb, or 500gb you may never need a hard drive.
You can defer on the hard drive unless you need to store large files such as video's.
It is easy to add a hard drive later.
Samsung EVO is a good choice for performance and reliability.
You will also need an OS; windows 10 64 bit.
You will also need a monitor keyboard and mouse.
FWIW:
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.
As a tip when screwing the motherboard into the posts, give the screw a small counterclockwise turn until you feel a click.
That lets you know that the screw will engage properly.
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.