Ocean Modifier Time Setting

It is not clear from the manual on what values need to be set in the Time field.
Is it “time” or “number of times”?

If it is to be keyframed what would be the initial value? And keyframes at what intervals?

Yes, to animate the ocean you have to keyframe the Time value.
So for example: Keyframe at frame 0 with value 1 and Keyframe at frame 20 with value 3.
Then go to the Graph Editor, make the keyframes Linear, and in the Graph/N-Panel add a modifier to the f-curve, selecting Cycles - Repeat with Offset for both keys.
In order to see the speed real time, make sure you have ‘Frame Dropping’ selected in the Timeline. Now start playing with making the f-curve steeper (=faster Ocean movement) or less steep,
or change the value for the second keyframe in the Graph/N-Panel while playing the animation (Alt-A).