When I configure a Cisco router using Cisco's IOS, I write my configs in a text file, then copy and paste them into the router. This enables me to keep a copy of my configs and it makes it easier to edit them. You can do the same thing with the EdgeRouter, copying configs from Ubiquiti's support site, editing as needed and pasting them into the router. Once they get the hang of it, many folks think working with a CLI is faster than a GUI.
EdgeOS configuration guides and examples can be found on Ubiquiti's Community Knowledge Base. There you'll find 24 FAQs, 50 CLI Basics, and 30 Config Examples to help you get your EdgeRouter up and running.
Resetting the EdgeRouter Pro to factory defaults and applying a wizard provides a good amount of functionality out of the box. The "WAN+2LAN" wizard in the GUI sets up DHCP, two LAN interfaces (eth0 and eth2) and one WAN interface (eth1), with both LAN interfaces NAT-ed out the WAN interface.
Below is a screenshot outlining the various configuration menus. Hitting the question mark (?) at any time in EdgeOS configuration mode provides a list of configuration options available at that level. For example, to see interface configuration options, you can start by typing set interfaces ?.
I found the EdgeOS GUI a useful complement to the CLI. Ubiquiti provides a 57 page user guide for the EdgeOS GUI. I found firewall configurations were easy to apply via the GUI. The EdgeOS GUI also has some useful utilities, such as the dashboard which displays numerous details such as Tx/Rx rates on interfaces, interface stats and IP addresses, shown below.
At its core, the EdgeRouter Pro is running on Linux. Thus, standard Linux file commands and tools are available. Further, you can write and run Linux shell scripts from the router. The Internet is a vast resource of Linux instructions and how-to's if you're willing to look. In addition, the Vyatta and Ubiquiti community have created quite a few configurations, utilities, and scripts, free to copy and try as you wish.
There are eight physical interfaces on the EdgeRouter, labeled eth0-eth07. With eight physical interfaces, the Edge Router Pro can physically connect to quite a few networks. All interfaces can be given a static IP address, get an IP address via DHCP and support a DHCP server.
802.1q sub-interfaces can also be created, allowing the Edge Router Pro to connect to a trunk port on an 802.1q switch and route between even more networks. According to the folks at Ubiquiti, the maximum number of VLANs supported on the Edge is 4096, although the real limit is dictated by CPU and memory consumption.
I successfully tested the Edge Router Pro's VLAN trunking capability by setting up a physical interface with two sub-interfaces corresponding to three different VLANs. I also set up a DHCP server on the Edge for each of these three VLANs. I connected the EdgeRouter Pro physical interface to a trunk port on a Cisco SG200-28 switch configured with the same VLAN IDs I set up on the EdgeRouter Pro. Plugging a PC into access ports on the switch assigned to each of the VLANs got an IP address from the correct DHCP server on the EdgeRouter Pro, validating VLAN tagging was working as expected.