You can dilute it a dozen different ways, as with many developers. If you want to use it one shot, then I would dilute it at least 1:1 to get the most out of it.
But you can replenish it and use it straight, which may be a better option in some cases. In that case, you make an initial stock solution from the regular D-76 pouch, or make it yourself with powders. You also mix up a separate bottle of replenisher, which uses a different recipe. I am pretty sure you can still buy it from Kodak, though if not, you can make it yourself. For every so may rolls (others can give you the details, as I am not sure) you add a certain amount of replenisher, after dumping enough of the stock solution to make room for it.
Some people swear by replenishment. I am sure this thread will get into it, but if not, you can search the archives for information.
I used to use it mostly at 1:1 and 1:3 one shot, and sometimes straight reused, adding time for every so many rolls, as Kodak recommends.
One more thing. IME, whenever a manufacturer states a minimum amount of developer stock or concentrate per roll for the working solution, it can be halved and still allow completely normal development. For instance, Rodinal minimum is 10 mL. 5 mL works fine. HC-110 is 6 mL syrup. 3 mL works fine. D-76 is 4 oz. 2 oz. works fine. And so on and so forth with most other run-of-the-mill developers.