If anyone works at Subway Restaurant or knows anything about it can you help me?

I'm applying for a job at Subway and I'm wondering about the shifts. How long are the shifts they offer for part time employees?

Also on the application where it lists off the days of the week what do I put there? Are those the days I will definitely work or just days I can work? And lastly If I'm available to work for 15 hours per week and I'm working for 4 days a week how long would/could my shifts be?If anyone works at Subway Restaurant or knows anything about it can you help me?
Our you only able to work 15 because of your age or because your working a second job usually if its because you can only work specific days and times put those in those days and times other wise they will know due to your age you can only work 15 hrs a week a fill it in for you so you could put open in the spaces just one big word open across the boxes.