isssue to access internet

[pat77550]

hello all,

I have a FortiGate 100F, I have a problem accessing my internet from my lan, when I plug in a pc, I have an APIPA address while I have configured the DHCP, I have configured a policy, internal to all, from LAN to WAN1, I opened all accesses at first to check and it does not work.
Do I have to create a rule in the rules from WAN1 to Internal?
However from my forti, when I ping 8.8.8.8 and www.google.fr, everything is OK, but from my LAN I do not have an IP address from my DHCP, and it tells me "No internet access".
In the DHCP DNS, do I have to enter the DNS of my internet provider? in the Forti DNS, do I have to enter the DNS of the Provider.
Could you help me please ?

Regards,