The time it takes to complete each day's activities will vary from person to person. It also varies depending on which resource you use (GMAT Prep Now videos or MGMAT books). Also, some days take longer to complete.

If you're having difficulties keeping up, don't worry. You can take longer than a day to complete the activities if you run out of time. Plus, later on in the Guide, much of your time is spent working on weaknesses (i.e., not learning new content).

NOTE: I recommend that you complete all of problems for one day before moving on to the next day's activities. Sticking to one concept at time before moving on to the next concept will help promote mastery of each topic.
It's also important to note that there are several math topics that build on previous math topics, so it's a good idea to build a strong foundation before moving on.

I hope that helps.

Cheers,
Brent