Well, that is the problem. You will not get many landings each month, but you should aggressively seek them. I see FO's turn landings down. I never did that as an FO.
Be a sponge, ask questions, study on your own, etc.
The 747 is tricky because we land at weights from empty to max landing weight. But don't be intimidated either as it is not a difficult plane to fly. It is just big. Learn to stay on center line at all times, develop strict aileron discipline, and strive to be smooth. The jet has a lot of inertia and you have to respect that. You can't pull it out at the bottom like you can in smaller aircraft. And your worst enemy is fatigue. You will rarely be on your A game.