There’s a lot of T-nation articles on the subject. To keep things simple I’d combine the approaches of this article,
And this one,
And the things I’d combine would be
When trying to add muscle we’re shooting for a weekly increase of 0.5-1 pound of scale weight.
As you progress through your mass phase your calorie needs will adjust. Continue to monitor scale weight and adjust based on that. Not gaining quickly enough? Increase by 250-500 calories a day (lower end for smaller guys and higher end for bigger guys).,