Grab latest copy of YAML from the Releases page and use your favorite deployment tool (such as kapp or kubectl) to install it.
Example:
$ kapp deploy -a sg -f https://github.com/carvel-dev/secretgen-controller/releases/latest/download/release.yml
or
$ kubectl apply -f https://github.com/carvel-dev/secretgen-controller/releases/latest/download/release.yml
release.yml
is produced with ytt and kbld at the time of the release. You can use these tools yourself and customize secretgen-controller configuration if default one does not fit your needs.
Example:
$ git clone ...
$ kapp deploy -a sg -f <(ytt -f config/ | kbld -f-)
Next: Walkthrough