If you are looking to do it via an integration, you would need to generate a script that can do all of the work for you.
You would need to plan out your board structure first to make it simple for you otherwise you will just have a lot of data in a board that doesn’t really make sense.
You would essentially need to do something along the lines of:
Get the data from Podio - API/Export
Read the data from Podio if yo have used an export function
Work out what data you have, and where it needs to go in monday.
Use the monday API to create items/upload files, etc… in the relative boards.
It is a general overview as I don’t have too much information to go on. Does this help you in any way? If not, happy to answer any more questions that you have.