I think there is still a dd-wrt wiki for this but I haven't looked at it in ages --

Using build K3.x-r27360 (06/18/15)  ... but same applies for any build that supports RB.
My steps in the order I do them for Repeater Bridge worked fine on WNDR3700v3, E2500, E1200v2:
Reset router
Disable WAN
Name Router
Set an IP address not being used within my subnet
Set gateway to main router IP that has the WAN connection
Local DNS to same as gateway
Check box for assign WAN port to switch
Disable DHCP Server
Uncheck everything associated with DHCP
Set time zone
Click Save
Advance routing set to 'Router'
Click Save
Click Apply Settings
Set comper to static IP in same subnet and log back into router
In 'Services' disable DNSMasq
Apply Settings
Wireless Advance Settings and this is just something I do cause it's just what I do
Disable CTS, Preamble to Short, Shortslot Overide to Short, TX Power to 13
Apply Settings
Status - Wireless - Site Survey - join what I want to connect to
Wireless Basic Settings, Wireless Mode = Repeater Bridge
Save
Wireless Network Mode = NG-Mixed (I match what I'm connected to)
ACK timing = 0
Save
Wireless Security - I always use WPA2 Personal-AES = to what I'm trying to connect to.
Save - Apply Settings
Check wireless status that I'm connected
Set comper back to DHCP - all checks good, can browser the internet ok.
Create VAP, Save, Apply Settings
VAP shows broadcasting on my phone but will not obtain IP --- Reboot Router!!!
Connects fine using my phone. Can browse internet without a problem.
Tell phone to forget the wireless network (VAP) I was just connected to and turn phone wireless off.
Enable WPA2 AES security for the VAP -- using different password than Wl0
Save - Apply Settings - Reboot Router!
Turn phone WiFi back on and locate my new secure VAP, type in its security and it connects without a problem.
All working good.

In this particular setup I am using a E1200v2 in repeater bridge mode connected to the VAP of a E2500 in 
repeater bridge mode to my main router which is a WNDR3700v4 running build r27360.
Using my phone thru all this I can still max out my WAN connection at 12.3 mbps down at testmy.net
That's as good as I got from my ISP and as good as I can get from desktop connecetd directly to main router.

'bout all I know