TrueNAS
The TrueCharts catalog is discontinued. Install Unpackerr with Portainer, Dockge, or a custom app.
Portainer
On TrueNAS SCALE ElectricEel and later (and TrueNAS Community Edition), Docker containers are supported. To simplify installation, install a container manager such as Portainer or Dockge from the built-in application catalogue. This guide uses Portainer.

Generate docker-compose.yml with the Unpackerr config generator
or write it yourself. See Docker Compose for a minimal
example. Map the same download folder your Starr apps use, and set user: to
the correct uid and gid.
In Portainer, navigate to stacks, and add a new stack.

Name it unpackerr and paste the contents of your compose file.

Confirm the host directory mapping and user/group IDs for your TrueNAS instance, then create the stack.

Portainer deploys the stack from here. When it is running, open the unpackerr stack and review the logs. You should see pending files for connected applications being extracted.

TrueNAS Custom App
There may be a way to install Unpackerr directly without a container manager. If you work that out, please edit this page so others can benefit from your tribulations.