I will try to help you as best as I can. So, it seems you have already chosen the processor and gpu.
After that you need to choose the motherboard, there are a lot of brands, but 1st you need to check the socket your processor matches. Looking in the Intel web page for your processor (
Intel® Core™ i7-10700K Processor (16M Cache, up to 5.10 GHz) Product Specifications) its socket is a FCLGA1200. There are a lot of good brands and models, in my case I have an Asus Strix motherboard, in Asus's models you need to look for the Z490 Series, thats the motherboard that supports your processor's socket. In basic words a socket is the port or place where you're going to conect the processor. Using a wrong socket model may result in your processor not working at all or not being able to give all the performance you want. Now, inside the Z490 series are several models depending of what you plan to do with your PC. (Asus Z490
ASUS Z490 series)
You could choose another brand of course, there is Gigabyte/Aourus, and several others. But be careful with the socket that matches your processor.
Pay attention, the model you're listing has a 'K' in its name, that means you can overclock it, i.e you can modify its frecuency to a higher one but that results in higher temperatures and maybe inestability. If you are new to pc's or overclocking I would suggest to change the processor for a version without K, or just don't touch that setting.
Now, a cooling solution for the processor, intel's stock air cooler is kind of meh during the last generations, if you want a better air cooler you may look for Nuctua, Cooler Master brands. If you're looking for water cooling, there are a lot of brands and models in market. I myself have a Cooler Master 212 Evo that works great, it is like the best classic 3rd market air coooler.
Now, memory, RAM. Nowadays the basic needs of ram is about 8GB but I would suggest 16GB (if you can buy more and your motherboard supports it maybe 32GB, more that that is a waste for the normal day user.), the current generation of RAM is DDR4 and it is very meanstream, so it will be compatible with your components. Again, there are several brands. I would go for Corsair or G. Skill Trident Z, again, several models for each brand; look for the frecuency, 3000MHz or higher, if there's a budget, 3200MHz is more than enough. Don't get me wrrong, you can work and play games with 8GB 3000MHz, but I like to see to the future and it may be worth to go for 16GB of RAM. Pay attention to your motherboards manual to put the memory stick or sticks in the right motherboard slots, so the memory can perform as desired.
HDD and SDD's. Not much there, it depends of your needs. In my case I have a 480GB SSD where I installed Windows and some programs. Games, music, pictures, etc ,are stored in a mechanical Toshiba 2TB HDD. In SSD's I would look for Kingston but the Adata brand I have has worked very good so far for me. In mechanical HDD's, Toshiba and Western Digital are the best ones for me. Seagate is good also, but for me Toshiba and WD are better. There are also other types of solid state drives, M.2 Nve, etc. I personally don't have much experience with that.
Power supply, well, it depends of how may watts your system will draw, the most crucial components are the CPU and GPU. Intel I7 10700k you list has a TDP of 125W.The Nvidia 3070 has a 220W TDP and needs a suggested powersupply of 550W minimun. This is kind of dynamic, your PC will not draw all the 220W all the time, just when your CPU and/or GPU have a lot of work to do, like playing high demanding games, if you're using Microsoft Word or other programs it will draw a lot less. But in general is better to have a "high" watt powersupply for "room". I would suggest maybe 600W of 750W minimun. In brands, again Corsair, EVGA, Seasonic, etc. I have an 600W EVGA 80 plus. There are several models,
but a rule of thumb and good practice is to not go cheap with the powersupply, choose the best brand and model you can, the power supply is the 1st shield against an electric problem and if you buy a cheap psu you risk your PC to go smoke and fire.
Ok, I think I have resumed the main components here. If you are looking for advices or tutorials of guide for a PC build you can go to youtube and search for Linus Tech Tips, Jayztwocents, Bitwit, Gamers Nexus, for me they are the 4 TOP tech/PC channels on youtube. They have A LOT of videos about pc parts, reviews, how to build a pc even if you're a beginner, I spent a lot of hours searching in those channels for advice and guide. Linus also has a web site with a forum where you can ask for help.
There is also this site
https://pcpartpicker.com/list/ where you can select parts or build a pc with your desired components, brands, models, etc. It literally has all the brands, parts and models in market. It will tell you about compatibilty issues if you choose the wrong part, power consumption, etc.
I hope I helped you with the PC build journey, it may seem like very complex at first but once you start and collect information, ask here, or forums, it really becomes a building lego work. Don't be afraid to build it nor ask for information, I was like you like a couple of years ago when I also went for my first build and so far so good, I haven't had any problem with my PC related to hardware.
Just in case, or for guiding porpuses I will leave my PC specs here:
CPU: AMD Ryzen 5 2600X
Motherboard: Asus Strix X470 F gaming (this series and model is only for AMD processors, Intel's use another "code")
GPU: MSI GTX1060 6GB
RAM: Corsair dominator Platinum 8GB 3000MHz DDR4
HDD: Toshiba Red 2TB @7500rpm
SSD: ADATA SU 480GB
Power Supply: EVGA 80 plus 600W
CPU Cooler: Cooler Master 212 Evo
