DataMapper ORM v1.8.0

[eluser]Syahzul[/eluser]
i would like to use it to create nested categories for my apps, but a bit lost even after reading the guide. i'm not an experienced programmer, if there's any sample code i can refer, that would be very helpful. i've check all cms made by CI (pyro, excite, bonfire), if i'm not mistaken, none of them is using nestedsets.