I'm afraid that most of the things on this site would be way over your head right now.
It's a good thing that you ride your bike, it'll help with getting rid of fat, but it's not enough for building leg mass, esp. for football.
All the exercises I'm about to write about, can be found either on this site or by google.
You have plenty of options with just the dummbells, you can do: DB Squats, DB Overhead Squats, Lunges, Step-ups, DB Romanian Deadlifts, DB Military Press, DB Clean & Press, DB Rows or Renegade Rows.
You can try them all if you want, for 3-4 sets of 8 and 1 minute rest in between. Do it every other day.
When you start lifting weights, your priority should be to learn how to correctly perform the following exercises: Full Back Squat, Deadlift, Romainan Deadlift, Bench Press, Barbell Row, Pulldown, Military Press (also called Front Press or Overhead Press).
Good program for start will be something like:
You keep alternating these workouts every other day, so one week you're doing Monday A, Wednesday B, Friday A, and next week you do Monday B, Wednesday A, Friday B.
Do 4-5 sets of 8 of each exercise, starting very light, and increasing weight for the next set as long as your form is ok. Because you're so young, I think it would be best to have someone knowlegeable check your form in person.
Good luck and be patient.