Begin by gathering a clean glass jar, a kitchen scale, flour and filtered water. While the process of making your own sourdough starter may take a few days, it's really quite simple and will only take a few moments each day.
Mix 50g flour and 50g water. After mixing, cover loosely and wait 24 hours.
After 24 hours, discard half. Feed your starter 50g water and 50g flour again, stir and loosely cover and wait 24 more hours
Repeat the above process 3-6 more days, increase the amount of flour and water if you're finding that your starter is peaking much sooner than 24 hours.
By day 7-10 you should have a bubbly, active starter! You will know it's ready if it double/peaks within 6 hours of feeding. You should be able to bake your first loaf this day! Once you have your starter, you can keep it indefinitely. Just take care of it!