Rebuilding Ticket-App - theme missing

I haven't really worked with Sencha cmd before, but would like to start.

This is likely an easy problem for seasoned cmd users.

I'm trying to build the ticket-app from the 5.0.0-GPL package.

I installed the latest version of Sencha cmd and changed to the examples/ticket-app folder (in the root directory).

When I execute sencha app build I get the following output

Code:

Sencha Cmd v5.0.0.160[INF] Processing Build Descriptor : default
[WRN] Failed to resolve package sencha-core
[WRN] Failed to resolve package ext-theme-neptune
[WRN] Failed to resolve package sencha-charts
[ERR] Theme "ext-theme-neptune" not found
[ERR] Required package "ext-theme-neptune" not found

Where do I have to put the themes?