@guyd2
1. Create VLAN 20 (CAM), create DHCP assignment for your NVR, plug into tp-link switch port and change that port from 'All' to 'CAM'. This is because nearly all of the Hikvision NVR's and Cameras are NOT VLAN aware, and thus we have to configure 'port based VLANs'. From what you say, this has already been correctly done.
2. The default network for the PoE ports of the NVR are on the 192.168.254.1 / 24 subnet, so if you are connecting the cams directly to the NVR PoE ports, then I suggest you use Hikvision's SADP to to give them a STATIC IP of 192.168.254.2 ....5 (the .1 is reserved for the NVR internal gateway). If you cannot see the cams when using the SADP tool, then reset them using the button on the camera and try again. The camera's default IP on reset is normally 192.168.1.64, so if you still can't see them, then TEMPORARILY change your computer IP4 address to be on the same ',1' subnet e.g. change your computers IP4 address to 192.168.1.100. Try the SADP tool again. When done, change back your computers IP4 address setting to what they were originally.
3. Plug the cams into NVR ports 1 to 4 going from 192.168.254.2 to 5. Open up the UI for the NVR and check cams are able to be viewed, you might have to select the correct video stream to view on the UI.
4. To acess the cams across PC's or other devices, you can either use a) the NVR GUI or b) install iVMS-4200 or c) access individual cameras via the correct port number (see point 5 below)
5. To optionally access the individual cameras, you will need to enable the 'Virtual Host' on the NVR via 'Device Access > Device > Video Device > .... More > Virtual Host Configuration' and enable 'Virtual Host'. You will now see links in the 'Connect' column and you can click on these to view / configure each camera individually. You don't have to go via the NVR UI - just copy the link and paste into a browser, and save a bookmark.
6. A further note, if you are insistent that the cameras go via the PoE ports and some/all of your cameras are NOT plugged directly into the rear of your NVR but go via a tp-link switch(es), then there may be further network config to do as the cams are not VLAN aware. We need to create a 254 vlan (NOT interface) as part of the tp-link wired network (on switches only, not gateway) and implement switch port changes to use the 254 vlan i.e. implement port based vlan 254. All of the above (point 6) isn't absolutely necessary if ports are set to 'All' but it makes it easier for us to isolate the vlan with rules. There is a more elegant solution, where the camera doesn't need to end up referencing the rear PoE ports but can sit on your CAM vlan and connect to your NVR but that it the subject for a different discussion.
7. Don't forget that tp-link's Omada setup allows crosstalk between vlans by default - so if you want to isolate your vlans, then you'll need to implements some switch ACL rules, not only to stop inter-vlan communication but also to allow the IP of any management PC's/phones/tablets to traverse across vlans, for NVR access.
Hope this helps. I'm traveling for the next 4 days, so won't get an opportunity to respond to any further questions until I arrive back on land.