I'll need to reread this a few times to grasp it.
If you could step onto that sideways path and remain in the same moment of "regular time," you might find that things could be slightly different—perhaps a different version of the same day. Moving along this perpendicular second path could let you explore different outcomes of that day without going backward or forward in time as we know it.
The existence of those different outcomes is the second dimension of time. The means to transition from one outcome to another is the third dimension.
This doesn't make sense to me. Time as we know it t1, time sideways t2, but why is the transition along t2 all of a sudden a third dimension? Wat?