@bob123321 

So I just managed to do this last night with 5 TL-SG308e switches.  It's a rather odd setup, but I think I've made heads or tails of it.  I'll try explain how it works and how it translates to other settings in other switches.

Untagged ports - These are the ports that you want to assign to a VLAN. These are the ports the switch will add the VLAN tag to the traffic. This is pretty straight forward to normal setups.

Tagged ports - These are your trunk ports.  What seems to be weird to me with this is every VLAN that you want to forward on the TRUNK lines need to be specified as tagged.

So, if you have VLAN100 setup with ports 2,3 and a trunk port of 8, you would setup VLAN100 with port 2 and port 3 as untagged, and port 8 as tagged.  Then if you have VLAN101 setup on port 4 and a trunk port of 8, you'd setup VLAN101 with port 4 untagged and port 8 as tagged.  The strange thing I found in the documentation, it says to leave all the ports defined as VLAN1 (default), but if you want to pass VLAN1 on your trunk line for a management network, you need to edit VLAN1 to change port 8 to tagged also.  I also had some strange DHCP cross over when I left all ports in VLAN1, so I only left ports I wasn't using in VLAN1 and ignored the notice from the documentation.  This would then give you port 8 as your trunk line and then ports 2, 3 in VLAN100 and port 4 in VLAN101, and ports 5,6,7 in VLAN1.

The weird part for me and the missing setup I had trouble with is the 802.1q PVID Setting.  As best as I can tell, this is where you actually assign the VLAN to the port.  So for my example setup under PVID Setting, set Port 2 and Port 3 to 100 for VLAN100 (assuming you used 100 as your ID) and the Port 4 to 101 for VLAN101.  Leave the rest set to 1.  The PVID Setting appears to be how it actually tags the VLAN ID onto the traffic.  Without it, my setup only worked with VLAN1 but once I setup the PVID everything across my VLANS worked well.

One thing I did do which may or may not be necessary was create all my VLANs on each switch.  Even if I didn't have any ports to define on that switch, I included it in the tagged ports just in case.

You also have to watch out that you can't assign the switches IP address to a VLAN. It always seems to stay on VLAN1, which made me change slightly how I setup my VLANs, but in the end it worked out.

It's definitely a strange setup process where you have to configure the same thing in 2 places, but it works pretty well once you understand that.  I hope this explains a little better how TP-Link settings translate to normal VLAN setups.