The WebUI on the TEW-673GRU is well done. It is simple and easy to navigate. TRENDnet has provided the basics as well as some nice advanced functions for more extreme users.
If you did not use the wizard or wanted to change your WAN type, you can do it from the Main-WAN page.
The time zone settings are more important than many people think. With another wireless router we had sync issues that at times prevented clients from connecting until we forced it to sync up with the time server. We have also seen a few routers that reset back to default at random. This also can cause clients to drop off or to have slow transfer rates (media streaming is seriously affected), so being able to set these right and have them stick is a good thing.
The rest of the items under the main tab are self-explanatory.
The items under the wireless networking tab are pretty simple. After using the wizard you will want to head here and setup security for your wireless networks.
For Security Cypher we recommend you use AES for the best security and performance. However, there are some older adapters (even N adapters) that do not like this cypher mode, so you might end up back at Auto. You can also change your WPS PIN and settings in this area.
The Status pages have information on your TEW-673GRU as well as detailed information on the amount of traffic going over the different connectivity points (LAN, 2.4GHz and 5GHz).
As you can probably guess, the routing section is where you would setup any static routes needed for your network. It is also where you can view the existing routing table in use by the TEW-673GRU. For most people this section will never be used, but it is nice to have for more advanced users.