10 weeks is long time.
Aim to run three times a week if possible, if not twice and one hard bike ride, (nonstop for 40-60 minutes).
One long run, start at your longest run today, say 30 minutes and add 5 minutes per week, 30, 35, 40, drop down to 35, then 40, 45, 50, drop down to 40, then 50, race. Don’t worry about distance! It’s time on your legs that counts.
Run once a week at 5:30/km pace, start at 15 mins and work/down as above.
Run once a week faster, say close to 5:00/km as you can. Warm up well, run for a minute, rest for two, repeat building up to 10 times, then start to reduce to resting time. 10 * 10 off 1 minute is the goal.
Run on grass/soft surface as much as you can. Warm up, warm down gently stretch if needed.
Good luck