[SOLVED] Choosing a motherboard is very confusing. Please help me!

[mooshroommanic]

Hi. To preface, I'm not very good with computer terminology, so please go easy on me. I recently bought some new components for my computer to upgrade it from ddr3 parts to ddr4 parts, so I can have higher end technology in the thing. I got the CPU, Ram, and even an SSD. My problem is with the motherboard. It's the most confusing part for me because there are so many aspects that I have to account for.
First of all, I already bought a motherboard but it turned out my CPU fan just didnt fit in it, so I had to return it. I now realize I need a motherboard with an AM4 slot. However, theres so many things to think about its really hard for me to understand it all. How do I know about the wattage? I dont even know where to begin with that but I heard its something you have to account for. Also, I don't even know if the motherboard I get will fit in my chassis. The motherboard previously mentioned was also pretty big and I wondered if it would even fit. It was much larger than the one I have currently, the 970m pro3.
I bought this computer pre-built (yes, i know) but since then have been upgrading it slowly over time. Another thing, how do I know if my ssd will fit in the motherboard I need? NVMe? PCIe? Gen3x4? All these terms mean nothing to me, its incredibly confusing. I know I should have gone through a bunch of tutorials on how to understand computers and their terminology a little better, but I feel like its much easier and more convenient to ask my questions directly than having to sift through 8 hours worth of tutorials. Please understand, I don't want to be the person who is blindly stumbling through the world of computers, it's just very confusing for me. Sorry.
I really appreciate if you can help me. The specs of the stuff i'm trying to install are as follows:
CPU: Ryzen 7 3800x
Ram: Vengeance RGB Pro
SSD: APS-SE20G 512gb
Current Motherboard (ddr3 one) 970m pro3
Current Graphics Card: 1070 ti
Current PSU: 700 br evga 80+ bronze
I'm sorry to dump all of this information on you, but I really don't want to mess up and buy another wrong motherboard... it truly is confusing and frustrating for me. Please help, i really appreciate it, truly. Thank you!

 

[extreme_noob]

Yes, you will need something with an AM4 CPU socket, and preferably a B450, X470, X570, or B550 chipset. Wattage is irrelevant to choosing board for the most part. And basically any B450, X470, X570, or B550 board will have at least one m.2 slot, which will fit that SSD.

Another thing to consider is bios version. If you buy X570 or B550, the board is 100% guaranteed to work out of the box with the 3800X. However, B450 or X470 boards were launched before the 3000 series was released, so those boards will need a bios version from a certain date to work with the 3000 series processors. MSI changed the names of some of their boards to include MAX, which means that it is guaranteed to have that bios version out of the box, and therefore work with 3000 series. Also, higher end B450 or X470 boards will have a feature called bios flashback, where you can update ("flash") the bios so that it will work. It's generally a simple process. And if your board is B450 or X470 non MAX, and has no bios flashback, you're still most likely going to get a board with a bios version that will work on 3000 series, as high volume vendors will mostly only have boards that were manufactured after 3000 series launch (a year ago) left in stock, which would have the correct bios version.