Domain replication.

My company is opening a branch and I?m setting up the domain replication so they may be still part of our domain. I already setup within the AD Sites and Services the Sites (2), Subnet (internal subnet of each site), Site link and moved the second server to the appropriate site . My question is: Where do I specify the WAN addresses of both sites so they may contact each other? Also, I replicated the DNS as a secondary DNS but it is giving me a lot of 4015 and 4515 errors. Any help will be appreciated.