So this confuses me

I quote:

"Fasting covers the period from sunrise to sunset. Imsak is the time when the fast begins and begins before sunrise. Imsak is also the time for the morning prayer, and eating and drinking should cease during this time."

In short; if fasting is between sunrise and sunset why does the fast start at imsak, which is hours before sunrise? Is eating and drinking not allowed between imsak and sunrise?

Both sentences are contradictory.

Would love to hear your opinions or better yet, the truth from a reputable source.