I am only a new user of Filemaker. I think that most people usually read from left to right - hence that is why it is good practice. It actually makes no difference to the data. The position on the chart has no significance whatsoever. It is only the relationship between the tables that matters.
Sounds like some one recommended "anchor buoy" table occurrence design. It's a good approach that I am using more and more with my new databases: http://sixfriedrice.com/wp/six-fried-rice-methodology-part-2-anchor-buoy-and-data-structures/
when should I use Alias tables?
If by "alias tables" you mean creating additional table occurrences that point to the same data source table, you create them whenever you need them. An Anchor Buoy format often requires creating additional Table Occurrences--so that's one reason. Even if you don't use that format, you typically need additional TO's whenever you need a second, but different relationship between two tables or when adding a relationship creates a "circular relationship" on your relationship graph.
If "table occurrence" is a new term: Tutorial: What are Table Occurrences?