The order of execution is only defined by dependencies between tables, regardless of on what tabs they are located. You can move a table to another tab but that won’t change the order of execution. Think of tabs as of sheets in Excel spreadsheet - they are just for logical grouping and convenience.
To sum it up:
In a table, actions executed left to right.
Derived tables are always executed after their source tables.
If an action (e.g. Merge) is using a result of another table, it will be executed only after the result is ready (i.e. after the other table is calculated).
Tabs don’t affect the execution order. Moving tabs left or right doesn’t change execution order.
@dgudkov excellent. Maybe you can append this to the Basic tutorial with a 1 minute video and because I think this really clears up a lot of questions I had about derived tables and why they are valuable. And if I don’t get this, I expect others did not get that either.