The more malt and sugars you put in your brew, the more alc is produced.
In my experience, to produce a 7% alc brew, you will need about 8lbs of sugars.
So 8lbs of DME, or 10lbs of LME because of the water.
Adding some steeping grains? About 1lb. will yield about .5% alc.
But look at some recipies for a style you like and add or remove some malt to get to the desired OG-FG.