Days 1 to 7
One lesson a day, in the place you said you'd do it, at the same time each day. Answer every prompt out loud. Don't take notes and don't pause to look things up; the method works because you keep moving. If a lesson felt shaky, repeat it the next day instead of moving on. On day seven, ask yourself three questions: Did I look forward to today's lesson or force it? Can I still use what I learned on day one? Have I actually spoken out loud this week? If the answers are bad, switch to your alternate program now rather than in month two.
Weeks 2 to 4
One lesson a day, five or six days a week. Repeat any lesson where you missed more than a few prompts. On one of your off days, do the short reading lesson that comes with the unit, so the written language stops looking like noise.
Weeks 5 to 8
You will finish the first level around here. Start the second the next day; the gap is where people quit. Add a two-minute habit: at the end of each day, say what you did today, out loud, in the language, badly. It gets less bad.
Weeks 9 to 12
Keep going through the second level at five lessons a week. Before day 90, have one real conversation with a person: a tutor, a language exchange partner, or a friend who speaks it. Pimsleur trains your mouth; that conversation is where you find out it worked.
Give it the full 90 before you judge it. The difference between people who learn a language and people who don't is rarely the program. It is whether they kept going after the first month.