I’m lost

I can’t install this package. I’m completly new to modx and I haven’t succeeded in installing any packages yet. I’ve successfully installed modx and it seems to run as supposed. I havent seen any output yet, though.
How to install Ditto? Installation notes say:
Installation:
1. - Copy assets/snippets/ditto to the corresponding location on your site
2. - Either create a new snippet titled Ditto with the contents of snippet.ditto.php or replace the contents of an existing snippet entitled Ditto to upgrade
3. - Repeat step 2 for Reflect
I’ve downloaded ditto-2.1.2-alpha3.transport.zip both manually and via the package manager. When using the package manager it says "not installed" and I don’t know how to proceed.
I’ve also tried unzipping the manually downloaded ditto-2.1.2-alpha3.transport.zip. There’s no asssets/snippets/ditto in this?
Also where’s the corresponding location on my site supposed to be?
Sidenotes
- where’s the best getting started tutorial?
- any getting started package avail?
Thanks
/Jesper