Hi @dfandrew
Adding to what @orangebucket mentioned, SmartApps are cloud-based, so they cannot be installed on the hub because the hub is hub-connected.
You can follow the tutorial below on how to create a SmartApp: Simple SmartApp Tutorial (SmartApp SDK)
There is a known ‘Network Error’ when updating the SmartApp that you will likely encounter. This can be resolved by uninstalling the SmartApp and reinstalling it.
Let us know if you have any questions!