I've been given crazy 0 to 1 projects - How can I scope them out and disambiguate them?

• Avoid the trap of needing to understand the code of an area before you start seriously scoping it out. Zoom out hard and view the project at a very high-level.
• Break down the project into the chunks you'll need. Each chunk should be able to comfortably fit into a task.
• Once you have these tasks, leverage other people! Find domain experts on each chunk and get their feedback on it, mainly how long it'll take and the risks. A lot of being a good project POC, especially on 0 to 1 projects, is just stitching the powers and knowledge of others together.
• After assembling all the knowledge, figure out the overall timeline and ask for more resources as necessary. For 0 to 1 projects in particular, the goal is to be not alone as quickly as possible, so you have a full-time behind the effort and don't need to solo carry everything.

Related resources:

• "What is the effective way to understand new repository in order to make the required changes in that repo?"
• "How do I create proper timelines and roadmaps for my projects?"