Boosting a post and hoping is not a marketing plan - it's a lottery ticket. Filling a retreat reliably comes from a system: a warm audience you've built trust with before you ever ask them to buy, launched on a timeline that gives people room to decide.
This is the real sequence, not the shortcut version. If you're still deciding whether your retreat will actually pay you, run the numbers first in the free Retreat Budget Calculator - marketing sells seats, but pricing decides whether those seats are worth selling.
Set up your Facebook Business Manager, a business page, and a linked Instagram before you have anything to sell. Create your ad account early too, even if you don't run ads on day one - platforms reward accounts with history and consistency over ones that appear out of nowhere the week of launch.