DDWRT Dual Network Creation with 1 Internet connection

Greetings my fellow technologists!

I have 2 routers and 1 internet connection, and want to set up a second wireless network using the same internet connection for VPN purposes.

The routers are:
Router A: TPLink TL-WR845N (non DD WRT flashed)
Router B: Linksys E2500 (DD WRT flashed).
Router A is connected directly to my company's network and works fine broadcasting its own wireless network (BENMAO).

BENMAO's Router A configuration settings are below.
LAN MAC: BC-D1-77-24-16-4A

I have connected Router B to Router A via Ethernet cable, Port 2 on Router A to INTERNET port on DDWRT Router B but get no internet access on Router B using DHCP with Automatic settings.

I am willing to change any settings and experiment to produce connectivity on the second network (BENMAOVPN) but don't know what to change in the protocol settings and there is very little information on Internet DDWRT forums.

It seems there are multiple DHCP, DNS and IP conflict issues which I don't really have a good grasp of here.

The DDWRT router (Router B) is highly customizable but I admit I don't know whether to set is as an Access Point, Client Bridge, Bridge, Repeater, or Ad Hoc, but I know I do NOT want to "cascade" the routers into 1 wireless network.

Also Router B probably needs to be set to function as a Router rather than a Gateway.

When I replace Router A with Router B its just plug and play: everything works fine and I can actually put all my devices on a wireless VPN, so setting up the wireless VPN is not the issue: its just getting Router B to accept the signal from Router A.

So bottom line is I need to know how to set Routers A & B to share the Internet signal from Router A to Router B, and then have Router B broadcasting a DIFFERENT network.

Thanks for any help in advance!