First of all - fear not! There are many ways to customize the pace of Foundations, and we encourage you to work at a pace that works for you and your student. What is important is providing frequent practice and making sure the student is comfortable with the pace, not completing a certain number of lessons per week.
Pay attention to your student and trust your sense of how he or she is doing. Don't be afraid to take a break from new instruction and spend a few days playing phonogram games and reading games, or doing phonemic awareness activities, to strengthen foundational skills before going on. The most important thing is to help the students develop mastery of the tools they need for reading (and to keep having fun while you do it!).
For some specific tips for slowing down, see the following article on the Logic of English blog: Adjusting the pace of Foundations lessons.
Priorities to keep in mind when setting your pace
The basic skills of phonemic awareness, phonics, and decoding (reading) and encoding (spelling) that these lessons teach are foundational to success in reading, writing, and academic learning. For students to develop fluency and reading comprehension, and then use these skills for reading in other subjects, they must know the phonograms so well and be able to blend and segment sounds so easily that their brains decode words automatically. Thus, it is far more important to give enough practice that students progress towards mastery than to "get through" a Foundations level in a certain amount of time.
To develop this mastery, students should be practicing the skills daily, especially the phonograms, but the best pace and amount of time to spend each day depends on the particular child or class. Students do not have to have every skill that has been introduced mastered before moving forward (the Mastery table at the beginning of each assessment is a helpful guide for this), but you want them to be getting fairly comfortable with what they have learned before introducing more. The best way to to this is short, frequent, varied, and fun practice.
A note about lesson length
Note that Foundations lessons gradually increase in length as you move through the program. We estimate about 30 minutes per lesson in A and B, 45-60 minutes in C, and 90 minutes in D.
One reason for this is that once students begin to have enough linguistic tools to read, it is through extensive reading practice that they develop fluency. Depending on the age of the child and your schedule, it may work well to spend more time each day as you progress and do the same number of lessons per week. However, if you need to spread some lessons over multiple days, doing fewer lessons per week, as the material gets more challenging, this is just fine!