Think of it more like a figure of speech rather than literal advice. It's not like: Step One: Gain Strength. Step Two: Gain Muscle. If your goal is to "look more like a bodybuilder," 9 times out of 10 you should get bigger while also getting stronger.
Let's say six weeks goes by and you've gained strength without gaining size, it means you haven't been eating enough. On the other hand, if time goes by and you've been gaining bodyweight without increasing the weights you're lifting, odds are you're adding more fat than muscle, which we don't want.
Not to sound like a dick, but i was 6'2" and 170 in high school and that's still very skinny. Please define "decent results".
How much bodyweight have you gained in the last eight weeks.
I know you said you're "not really that strong", but what are your current best lifts in the squat, deadlift, flat bench press, overhead press, row, and pull-up/pulldown?