Confused on Gulf war syndrome

As the title says, I’m confused on how the gulf war syndrome claim works. I would like to file for IBS, migraines, and possibly chronic fatigue. I have no diagnosis for any of these but Alotta times I see that migraines should be un diagnosed as well as Chronic Fatigue syndrome . I’m a gulf war vet with sinusitis and rhinitis connected but I’m wondering my best way to file and what should be my next step?