Does anyone know how to manually upgrade from V2.2 to V3 step by step? What files to move and where to move them to.
i think they’ll release an upgrade and they are still working on it
i’m waiting too 
b.r.
I worked on this all day.
I installed a clean installation of v3, created grids, blocks, and created a unique CSS in my_changes for design changes and kept the basic template untouched. I'm determined to NOT modify the files directly so future upgrades are painless (with very minor noted exceptions, notably the mail list subscription format tweak).
The big hurdle was importing the data from v2.
Caveats are in the user and product data - they have auto-incremented ID numbers that need to be updated, but aren't included in the Export/Import data.
A few hours of running SQL update queries and it's done and working. All data has been migrated to v3, including Abandoned Cart data. The only problem I have is that Abandoned Cart data, at the moment, has no pagination in the report.