First, I went to the salvation army but you can go to just about any thrift store and get a pair of old jeans, high wasted or not whatever you prefer.
Then, cutting the jeans can take a lot of time and patience especially when it comes to making it even on both sides. once you get them to the length you want them you can distress the ends with a scissor or just pull it apart with your hands.
Next, fill up a bucket outside half with bleach and half with water. make sure you are wearing gloves since bleach stains.
Then, put the shorts in the bucket, clipping them so only the bottom half is in the bleach. Let it sit in the bleach for a couple of hour.
After, take them out and let them air dry, then wash them and dry them again and they are ready to wear!