Since our shipping calculation feature is so flexible, able to accommodate a diverse array of shipping calculation methods, there really isn't a "one size fits all" tutorial aside from the general help page explaining our Shipping settings:
http://www.e-junkie.com/ej/help.shipping.htm
Just enable "Shipping/Buyer's Address" in the settings of each product that should trigger collection of a street address during checkout and apply your shipping calculation method. Existing products which do not have that setting enabled would not be affected.
When you go to Seller Admin > Cart Shipping Settings and click Next to reach the Shipping Rules screen, the Existing Shipping Rules menu will show the rules you've already created with the conditions an order must satisfy to qualify for that rule (if these conditions all show as zero for a given rule, that indicates no min/max order size is required to apply that rule). When you select any rule from that menu, the calculation method for that rule is shown underneath the menu itself.
Note that any rules you set for All Countries can be regarded as "international/rest of the world", as they would apply to all your chosen Shipping Destination countries that don't have a specific Rule of their own. You can choose which Shipping Destinations countries you will allow on the first screen of Cart Shipping Settings.
If you need more specific instructions, just reply here or email us to explain in detail how you want all your shipping rates to work, then we can explain exactly how to set that up.