Configuring an access point on a RE200 v3

Hello, I've managed to successfully install OpenWRT on my RE2000 however, I haven't managed to figure out and require assistance on how to set up a wireless access point to extend my main network as my device has a single ethernet port. Any help is appreciated.

The port is in lan, swap it to dhcp client and from new IP address add wifi access point(s) to lan network.

Thanks for your reply, I've done as you have instructed and it worked! However I can't access the device now with the new IP it gets from my router.

Did it get the new IP or it rolled back network settings....

You have 90 seconds to connect to new IP otherwise it rolls back.

Basic scheme:
Set dhcp client, wait for config to roll back, then it permits yoou to force change.