WAN VIP's

Looking to get information on how to setup 2 or more WAN IP's from my ISP on my WAN 1 port. I have read it can be done with VIPs? If I try and just set wan2 to another IP I get a subnet mask overlap issue. Ultimately want to be able to have a server behind the firewall accessible directly on a global IP and have another one setup for VPN both remote and site-to-site. I like the option of leaving wan2 open for a second ISP and fail over. I currently have a new Fortigate 60E but I am rather new to the Fortigate world.

Best,