When starting to learn scales the first thing we need to know is the fingering. What is fingering you ask? Basically it's an efficient system that lets you know which finger goes on what key so that the motion of the hand is as smooth as possible and without stumbling on your own fingers. This fingering is made easy to understand with the help of numbers from 1 to 5, 1 being the thumb (on both right and left hand) and 5 being the pinky finger as shown bellow:
Keep in mind that these fingerings are the general accepted standard, some of them might not be so efficient in a specific context. Keep your mind open and explore other possibilities if you need to.