Sonlight's Instructor's Guides provide you with all the schedules, questions, and notes you need to begin homeschooling your child immediately. In fact, you can teach your child for an entire year without adding or taking away anything that's already scheduled in the Instructor's Guides for your homeschool curriculum.
Your Instructor's Guides lay out exactly what you need to do every day for 180 days, but they are not the law. Rather, think of the Instructor's Guides as your launching point — a point from which you can quickly jump into learning and then tweak and modify as you go along.
If your child is struggling to keep up with the assignments in the Instructor's Guide, then feel free to scale back for a while. Either don't assign all the books or simply go at a slower pace.
If, on the other hand, your child is reading ahead in the books and needs more work, then feel free to supplement. Assign some of the read-alouds (books you read aloud to your children) as readers or seek out some extra books for your child to read. (If you're really seeking to do more, then help your child research and learn about a special interest she has.)
Your Instructor's Guides will save you hours of homeschool planning. However, in some cases, following them to a "T" could be inappropriate for your child. So plan for some flexibility. It's one of the keys to maximizing the value of your Instructor's Guides and home education.