I don't think you can do better than read Jacob's excellent guide for beginners:
http://forum.caravelgames.com/viewtopic.php?TopicID=28303
However, just by way of quick explanation, there are hundreds of holds made by users, many easy, many difficult, many fun and others not so fun. Jacob gives some good recommendations in his guide. Just check out the "
Downloads"
link at the top of the page, and then go to the "
Holds"
link at the bottom of the downloads page.
Also, each of the official games has a level editor and talented individuals made games using those editors. However, only games made prior to or for that game can be played in that game.
So for example, you can play any Architect Edition (AE) or Journey to Rooted Hold (JtRH) hold that people have made if you own JtRH. That's a good amount. But you cannot play The City Beneath (TCB) or any of the holds made using that editor, because it is newer. So it's best to buy TCB (the latest official DROD platform) so you can play any previous hold. However, you would have still had to buy JtRH to play it (but you can import it into TCB).
As to what order to play, I think you picked a good one to play first. There are many choices after that, or before you even finish that one there are other holds that will help you hone your skills.
All best to you and welcome to the forum!
____________________________
-Logan