Start with the "Why". Why would you use Scrum? I'm with Simon Wardley [1]. Agile, Lean and waterfall are not the same thing and are not exchangeable.
Agile is for building new things, it's optimized for learning and navigating in a space you don't know about (say before/around PMF) - though most people do Scrum wrong, E.g with the roadmap-anti-pattern.
Lean is for optimizing a product, after PMF, E.g. when Scaling.
Waterfall and Six Sigma is when you do the same thing over an over again and you have a lot of knowledge in the space, when you outsource commodity development,
E.g. customizing a CRM.
Agile is for building new things, it's optimized for learning and navigating in a space you don't know about (say before/around PMF) - though most people do Scrum wrong, E.g with the roadmap-anti-pattern.
Lean is for optimizing a product, after PMF, E.g. when Scaling.
Waterfall and Six Sigma is when you do the same thing over an over again and you have a lot of knowledge in the space, when you outsource commodity development, E.g. customizing a CRM.
[1] https://twitter.com/swardley/status/1215020984278888451