start by resetting your WRT1900 to defaults -- this way it is in a known state.
Connect it (by a wire from a LAN port) to your PC. Log in and change the IP address for the LAN (to 192.168.2.0). Immediately after you hit save and apply, on your PC network settings, click the button to renew your DHCP lease. That should update the PC to an address in the 192.168.2.0/24 range. Then, if it doesn't do it automatically, connect to 192.168.2.1 in your web browser. That will prevent the auto-rollback. (alternatively, if you don't want to have to worry about getting the timing right, you can search the forums for "disable auto rollback") -- but given that you are new to OpenWrt, it may be best to leave it as is.)
i wasnt being funny, nor autocorrect. Being said, I'm supposed to change from ipad to lan? My connection is being changed from ipad wifi to a wired connection?
I would like to setup my router for vpn (everything I need to do) then just unplug from laptop wired connection to either a wired or wireless connection to my home router.
i'm already ssh into router. Im sorry as you replied uci set network.lan.ipaddr='192.168.2.1' which led me to imply you were talking about ipad. I'm sorry if I wanted to clarify if you were talking about my ipad, or if it just happened to match in terms to my ipad.
ok... once that's done, you'll need to renew the DHCP lease on your computer. It should come back with a 192.168.2.0/24 address. From there, you can connect the WAN port of the OpenWrt router to the LAN port of the other router. It should have internet access and you can do whatever you want from there to setup your VPN.
keep the wire between your PC and your OpenWrt router connected. Makes sure you have an address with .2.x at the end. use your web browser to go to 192.168.2.1 -- does it work?