A starter is like a pet, and needs to be taken care of our your baking adventures could run into trouble quicker than you can say ‘why didn’t my load rise?’
Feeding a starter is simple, and should be done once a week.
A quick summary is mix equal parts starter, water and flour, leave out for an hour and then refrigerate. Any left over starter should be used in bread, pancakes, pikelets, pizza or with any other bready fun, or discarded (it feels weird the first time but you do get used to it).
Here’s a quick how to video: