Added FAQ

README.md

@@ -128,3 +128,21 @@ The installation package is created by running `download_dependencies.sh`. This
 ## Notes
 
 - We're not using the RHEL8 `root` package, due to the fact that they are built for python3.6, hence we need to build it with python3.8.
+
+## FAQ
+
+### How do I create a new installation package, using new versions of specific packages?
+
+1. Go to [Actions secrets and variables](https://github.com/cms-DQM/dqmgui_prod_deployment/settings/variables/actions).
+2. Edit the `Repository variables` to reflect the versions of the packages you want to include in the release. For example, if you want to use DQMGUI [`9.8.0`](https://github.com/cms-DQM/dqmgui_prod/releases/tag/9.8.0), change `DQMGUI_GIT_TAG` to `9.8.0`.
+3. Trigger the `build_installation_package` action [here](https://github.com/cms-DQM/dqmgui_prod_deployment/actions/workflows/build_installation_package.yaml): Click the topmost row of the "workflow runs" table, and in the new page that opens, click `Re-run all jobs`.
+
+### When do I need to re-trigger the GitHub actions of this repository?
+
+Two cases:
+
+1. You want to create a new release, which you cannot find under [Releases](https://github.com/cms-DQM/dqmgui_prod_deployment/releases). This means that you want to change a version of the packages downloaded, e.g.
+DQMGUI, or DMWM's deployment.
+
+2. You want to update an *existing* release (less common, probably for debugging reasons): The release you are
+looking for exists, but some of the packages downloaded in this release have been updated, using the same tag/reference/branch name. For example, if you want to include a development branch of DQMGUI (e.g. `dev`), the DQMGUI `dev` branch may be updated, but the installation package that has been created cloned an older version of the `dev` branch.