In order to use the Select statements as it says on the Tutorial, you need to open a connection and then refer to a table in that connection using the select statements.
If the tables have already been loaded in memory then you use resident to refer to them
Qlik will automatically concatenate tables that look the same and as Table1 and VTable look the same, you need to explicitly say not to concatenate.
The deletion of the tables at the end is for them not to link.
You should play with all these by placing those instructions as comments and see the difference,
I hope this helps,