No one can really tell you how long you should estimate doing something could take, given that only you know what you are familiar with.
That aside, adn (who developed snkrx) suggested that a game with a one month budget should choose a scope that can be implemented in half a week, and spend the rest of the time on polish.
Agreed, it'll depend on the team and your own preferences, and the amount of time you can commit, and your level of experience.
I'm not an expert, but here's a top-of-my-mind, napkin-sketch framework to think about.
(Some of these may overlap)
-> Team meeting (comms, responsibilities) (2 hours) (figure out how you'll communicate, how often, who does what, and how much is expected.)
-> Ideation (1-2 days) (It's vitally important to get everyone onboard with the premise, or you'll lose people along the way.)
-> Infrastructure (Engine, Git, etc) (<1 day) (Is everyone familiar with the game engine and version control? Who will act as the steward of the main branch?)
-> Rapid Prototype (2-3 days) (Don't worry about architecture, just get something working. Worst case scenario, you can publish this if everything goes sideways after this.)
-> Refactoring (1 week) (Now you worry about architecture, coding standards, folder hierarchies, etc.)
-> Bugfixing (1 week) (Always more bugs than you think. Tackle the hardest ones first.)
-> Polishing (1 week) (Takes longer than expected. You should have a UI, theme, menu system, levels, add juice, then add more juice)
-> Publishing (1-2 days, but start early) (export and test, export and test. deployment usually takes longer than you think.)
-> Marketing (2 days) (someone makes a trailer and makes the page look nice on Itch.io. Hallmarks of quality, often overlooked.)
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Side note: It's common for teammates to wait until they get a request for assets. There's no reason to wait. Everyone should be producing something all the time, (time-permitting).
