DHCP relay from firewall subnet to DHCP server on another subnet

Hi all

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I want to setup my wireless AP's to hang off my sonicwall firewall, so I can have more secure wifi for compliance. I will have SSID's for Corp, BYOD and Guest.

I want clients on the Corp wifi to be able to get DHCP from a windows DHCP server on another subnet that is on my L3 switches.The corp wifi will be on subnet 10.5.13.x/24 off a LAN interface on my sonicwall and the Windows DHCP server is on 10.5.5.x/24. 

The 10.5.12.x subnet does not currently exist on the L3 switches and the only link between the switch and firewall is the internal interface of the firewall,  which is on subnet 10.5.50.x/24.

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What do I need to do on the L3 switches to enable my 10.5.13.x clients to get DHCP from the windows server? I am aware of how to setup DHCP relay on the sonicwall FW, but I do not know whether anything needs to happen on the switches.

I have included a diagram for clarity.

https://imgur.com/Y13zSeh

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Thanks