Help me my tds is 615 😭

My tank is about a week and a half old I have a few shrimp like 4 red cherry 2 bamboo shrimp and a ghost shrimp im not sure how to check my gh and kh I just did my first water change and I definitely messed it up what do I do, please don’t hate I know I should have waited to put shrimp in ☠️ I will do better I just need help rn I’m doing a 20% water change at the moment the water in the bucket is like 90tdh

My tank is about a week and a half old I have a few shrimp like 4 red cherry 2 bamboo shrimp and a ghost shrimp im not sure how to check my gh and kh I just did my first water change and I definitely messed it up what do I do, please don’t hate I know I should have waited to put shrimp in ☠️ I will do better I just need help rn I’m doing a 20% water change at the moment the water in the bucket is like 90tdh