There is magic to a small time frame. Motivation goes way up as you'll want to make each week and each lesson count.
To make progress, commit to yourself you CAN DO THIS. Block out 30 minutes at a time, 4 times a week in a row.
You are gonna sit down and tell yourself "only 5 minutes" and see your attention span grow into 30 minutes. Somedays you will feel it and maybe go longer, time will flow and fly by. Somedays you won't feel it at all but you will be at the piano. And that "not feeling it" 5-minute day will keep you from going backward.
Example #1 ) M, T, W, TH
OR
Example #2) TH, FRI, SAT, SUN
Ideally, you would want every day, the more the better but 4 days is a good minimum. You will WANT to play. Especially because you know you have the group with you only for 6 weeks.
If you skip a day accidentally make it up the next day and in travel weeks or weird schedules, double up on weekends or other days.