NAT rule issue with my Fortinet 60C

Hi All, I configured a Fortigate 60C. This one connected to Broadband Modem to get internet connection thru WAN1 port. From internet I could accessed to Firewall Web-Console thru Wan1 interface with using NAT rule in modem but couldn' t get in a PC inside LAN network. Had setup Virtual IP and Policy as followed a lot internet searching and advising. Any idea to help me out with this issue? Thanks a lot. Note: - Policy already allowed any from WAN to Internet with ALL Accept. - Virtual IP rule has pointed to Destination IP LAN. - Standing at Modem can' t ping to PC inside LAN (I don' t know how to setup ping policy can go thru). Thanks.