It all depends on what your metabolism is like. Determine what you need to eat to maintain, using known data or estimating from your current calorie consumption and weight fluctuations. The less muscle mass you have the more you can likely gain while bulking compared to more advanced lifters/users.
If you're newer to AAS and smaller try to shoot for two pounds per week, provided you aren't gaining too much fat. If you're more advanced shoot for .5 to 1 pound per week, assuming the same.
If you're relatively small and new to AAS, and you do a hardcore blast with AAS you can likely gain upwards of four pounds per week. This gain in weight shouldn't be considered during the first week or so or oral use, as the water weight will shoot up quickly, but this isn't tissue accumulation.
Anyway, to answer the question more simply, just eat as much food as is necessary to gain mass as fast as possible while remaining in your acceptable fat gain range. If you're feeling like you can gain more weight then eat more food, and vice versa.
There is no way you can tell someone using AAS to eat 5000 calories per day and not know anything about their body statistics, cycle specifics, daily activities, etc.