You need...
1. 24 Port SWITCH (don't buy a hub) from eBay for less than $50. Any base 100 is more than enough. Gigabit is stupid unless you plan on using this switch/connection for video streaming/file transfers. I am partial to netgear prosafe gear. Like this... this is the bottom of the barrel.
https://www.ebay.com/itm/NETGEAR-JFS524-24-PORT-10-100-MBPS-FAST-ETHERNET-SWITCH-RACK-MOUNT/272985695841?hash=item3f8f372661:g:RzgAAOSwfVhaNYz82. Buy pre made cables unless you have made your own prior. Avoid the headaches and rookie mistakes if you don't have the tools and testers/know how.
3. Use any router your comfortable with that IS STABLE! Personally I would buy a ddwrt/openwrt compatible unit, dump the oem junk firmware and put an open source setup on it...but this is a bit advanced. Main point here is stability due to a single point failure taking down the setup. You invested some serious coin in miners, the network must be robust to avoid issues. I would either buy a new residential grade unit or a good used business unit. I would steer clear of used cheap residential units from ebay.
4. Set router to DHCP (automatic address), set router IP to 192.168.0.1. Set DHCP range to 192.168.0.101-192.168.0.150 (or whatever max you wish). Number miner 1 as 192.168.0.101 (so you know ip 101 = miner 1, 102 = 2 and so on. I prefer to use the highest ip for the pc, then smash the ip range down so no spares are left.
5. Set all miner ip's manually prior to connecting via a laptop/desktop or only plugging one in at a time after step 6 (you can do it after all plugged in but not sure if miner default ip is inside the router's range, prior to plugging in is foolproof but tedious)
6. Plug it all in to your internet modem or whatever, turn on router & switch... and behold the magic
This is BS...
Most routers will except whatever manual IP address you assign to each miner WRONG! If miner ip is outside router range...not possible. All residential routers default to the smallest subnet mask, requiring the first 3 sections of the ip address to be exact. If you plug in a virgin, default miner that is outside the range your screwed. If you don't know the miner default address it is more work. If all miners are virgin, default plug only one in at a time as all default to the same address. 20 virgins being turned on at the same time will result in ip collisions and failure or a really good time if your mind is in the gutter.
This works but will be no fun...
you can enable each miner to use DHCP then inside the router assign the static IP address based on the miner's MAC address. Either way will allow you to know exactly what IP address is going to what machine. Routers using DHCP can make address reservations, not assign static addresses to hardware. This method is not foolproof, requires all miner MAC to be documented/figured out after the fact, and is not permenant. Imagine a pile of spaghetti and seperating it out to individual strands. If the router firmware updates, the DHCP table is corrupted, etc... your setup is toast. FYI... some routers do auto updates and wipe these settings without end users knowledge... and you be like WTF happened?
Closing thoughts...
Dedicated hardware requires dedicated power and network IP's to effectively manage it. Set static IP's if you want to keep it straight. Use DHCP if you don't care. Both work but one is easier to service. Make an excel document or download an ip template from the web to keep track of it. Goto a hardware store and get labels/#'s for your cables... life is much easier when this is done. Also properly color coded wires is a plus...yes there are codes, follow them. I know without a shadow of a doubt where every cable goes (due to #) and purpose (due to color) in my setup by looking at only the switch.
If you are USA based and want field service I charge fair rates and can send my T&C's across. Any pro should be able to take 20 miners from cardboard boxes to the network setup in less than 3 hours providing your power, cables, etc... are all done, long enough and ready. If you had your pool, credentials, etc.. ready they would be ready for individual baseline testing in no time.
If you have questions I give 3 for free, PM me.