Starting times... use the time for D-76 1+1,
and agitate once per minute. Agfa suggests 11',
that's as good a place to begin as any other. I've found that it is better to judge
E10 by the midtones rather than by Zone I. You may choose to agitate for 10 seconds every 5th minute if the APX highlights climb to high for your taste.

You've got three ways to use this stuff:
one-shot, re-use the developer for a given number of rolls, or replenish.

Use D-76 instructions for guidance here.

If you replenish, 'season' the developer before your first roll
by soaking 4 rolls of 135-36/120 (any old b&w film that has been fully exposed)
for 15 minutes or so, and carefully drain all the liquid back into the bottle.

Work with 2 liters of developer, one Working solution, and one Stock.
After your development is finished, pour the developer from the tank into a graduate,
stop, fix, and wash as usual.

Withdraw 3 oz of developer from the graduate, and replace it with Stock, then pour it back into the Working bottle.
It isn't much of a hassle, and makes a very nice working developer that will last indefinitely.