ipsec vpn to Head Office core switch vlan

[Salman_Baig]

fortiagte.jpg                 

i have 2 site site a hQ and site b Branch i well attached the snapshot of the networking 

i want to reachable to branch side to core lan site network please help how can i conectvity with remote branch lan to hq core lan side still site to site ipsec tunnel working fine both remote side lan pinable and pas the traffic but need remote branch lan to pinnable through the tunnel to hq lan side  all hq lan user gateway core switch and core switch gateway next hop firewall please help i well share the snapshot very urgent help me please  i m very worry about it