Changed LAN address in 'admin/network/network'

Could someone help me, please? I'm having a problem with BT Home Hub 5 type a with lede-17.01 preinstalled and bought the other day on eBay. I was a little confused in inputting ISP config (I'm only used to basic router config, nothing as bells & whistly as LEDE andLuCI). After finding that I couldn't get online I connected WAN to working router's LAN and attempted to ping lede project. The ping failed as, "bad address" so I had the bright idea to go into 'admin/network/network' and edit LAN to as I read that perhaps both routers may be using the same address. The bad thing I'm seeing is that I think that I'm now unable to connect to router on or Going back into history I can still see 'admin/network/network' page but trying to edit the LAN nothing will load.
Can anyone help?
Thank you.

It's alright, I've got working now. I just need to do more homework regarding basic setup. Can an Admin close this for me? Thanks.