how to contributions to this project

[dalei2019]

At present, there are few functions supported in the template, which cannot meet the needs very well.
I want to extend some common functions.
I don't know if there are any guide-like documents.
Will direct contributions to this project be automatically merged into the main argocd project?

[dalei2019]

current functions list : https://github.com/argoproj-labs/argocd-notifications/tree/master/expr .