There's no kind of soil to put over it to help it germinate. Lots of people do top dress, but that is a mistake. You don't need, or want, anything. The best thing you can do is lightly loosen the surface with a rake (very little pressure). Scatter the seed, roll it down with a water filled roller (rented), and water. Unless you live in south Florida or deep south Texas, wait until June to do this. Bermuda seed needs very warm soil to germinate. A lot of people put it down too early and blame the seed for poor coverage. If you put the seed down now you'll be disappointed for the next 6 weeks that it isn't sprouting. Then when the soil gets warm enough in June, it will sprout.

I guess I should ask why you are reseeding a bermuda lawn? Bermuda should never need to be reseeded. If you have too much shade in the yard, the bermuda will thin out, but adding more seed will not help reduce the amount of shade it gets. If you have shade, then bermuda is the wrong grass to be looking at. The only southern grass that will thrive in the shade is St Augustine.

Where do you live?

As mentioned Bermuda should not need reseeding. If you have thin spots in your Bermuda, something is wrong you need to address and seeding with Bermuda will do nothing.