If you have weights (bar or dumbbells) then Squats are the main one for legs, they work the majority but focus on the quadriceps (the main upper leg muscles).
Calf raises for... you guessed it calves.
Also lunges which work more the back of the upper leg (the Hamstrings).
To be a little clearer here:
The motion of a Squat (which you can look up online) is basically start in a standing position, legs roughly shoulder width apart and bend at your knees as if you are going to sit in a chair (you can even use a chair to start with to help with the motion/form) when you get to a point at which your upper legs are parallel with the floor (or roughly the same position they would be if you were sitting), stand up again, repeat as many times as you can. (Squats can be done without weight, but as with most muscle building exercise weights help... even if you just grab a couple of bags and put some things in them, roughly balance the bags so you have about the same weight in each hand and just hold those while you squat... it should help to add resistance).
Calf raises are basically just the motion of going on tip toes... but try and do it without wobbling, so from feet flat on the ground (again roughly shoulder width apart) slowly and in a controlled manner lift the heel of your foot of the ground by going further and further onto your toes... if you can find a block of wood to stand on you can place your toes on the block, your heels will sit on the ground, you then rise until you are on your toes and then lower again. Repeat as often as you can.
Lunges again start from a standing position (feet roughly shoulder width apart) and step as far forward as you can with one leg till your opposite knee is nearly touching the ground. Then bring the back leg up to the same spot as the leg that stretched forward. Next step the opposite leg as far forward as it can go, again the rear leg will drop to nearly touching the knee on the ground. Step the rear leg back to where the front leg is and continue as many as you can.
Be prepared to have a bit of muscle pain but know the difference between the pain of a trained muscle and the pain of a damaged muscle... take it slow, don't rush and if you haven't used weights before start slow and add weight only if you can easily perform the motions... don't go too heavy either as you need to make sure you can put the weights back down again safely at the end of the exercises.
I hope this helps... as I mentioned it can be worth looking up the exercises you want to try... you should be able to find some video clips of them being performed which will be very helpful when you start out. If you want to get serious about lifting weights I would recommend either visiting your doctor or at the very least a local gym and asking for advice especially based on your age. I began lifting weights around the same age, maybe a year older and was told that before a certain age there is some risk of stunting growth if you exercise with too much weight (essentially compresses the spine and prevents you reaching your full height potential)... but you can train quite safely with good guidance.
Good luck and I'm sure you will be doing justice to your chosen characters in no time!
