BGP Configuration Between Switch and firewall with two ISP at both end

[vyas.2020]

I am having cisco switch at my HO (3850 switch) and DC end it is fortigate firewall 

Both the end having two ISP for redundancy purpose

HO Side having two different router for different ISP and both link is terminated on cisco 3850 switch. 3850 I want to configure BGP. DC end also have same scenario.

I want to configure BGP between HO and DC where I need to configure BGP

Please find attachment for diagram

[MHM Cisco World]

no attachment, can you reattach again ?

[vyas.2020]

Diagram Attached