For the remaining 2/3 of the concentrate, add water to make one gallon. That's your replenisher.
Add 300ml replenisher per 30 8x10 prints, and top up the working solution to a full gallong at the end of your printing session if needed.
When you start a new batch, take the spent developer to dilute the 1/3 gallon of fresh concentrate to make new working solution.
Ethol will send you the instructions in the mail if you ask for it.