I have no idea what kind of fitness I need to do?

Hello I'm fairly skinny and petite but I have fallen into bad habits with my eating and I am keen to get stuck in to my exercisebut I haven't got a clue where to start ! Can anyone recommend a good daily routine that I could start out with to get me used to motivating myself? I need to know what type of exercise I need to do, also how long for, and how often? Thanks any help would be amazing