As a guide
5000 mg of sodium (not just salt)
1000 mg of potassium, in the form of potassium chloride or potassium sulfate
300 mg of magnesium, preferably in the form of magnesium citrate
All these electrolytes should be preferably consumed in addition from what you get from your food.
Most of us will not reach these suggested totals with food alone, but there are several ways to ingest extra electrolytes:
Drink 1 or 2 cups of bouillon or broth daily
Add salt and/or salt substitute to your food
Take a multivitamin containing magnesium and/or potassium
Add a teaspoon of salt and/or salt substitute to a large glass of water and drink it
This advice comes from a ketogenic diet site
https://www.reddit.com/r/ketogains/