Template Not Found Error With Custom Template in a Multi Module Project

II have a sbt g8 template that I customized for my projects and this is located as one of the sub project in a multi module scala sbt project which is assigned to my organization. For example.,

main-project
- projec1
- sbt-template-project.g8
- some-other-project

The main-project is available in my git repo and I would like to know how I can create a project from the sbt-template-project? I tried the following, but it says "Template Not Found":

sbt new file:https://github.com/my-organization/main-project/tree/master/sbt-template-project.g8

I also tried:

sbt new file:https://github.com/my-organization/main-project/sbt-template-project.g8

I also tried:

sbt new https://github.com/my-organization/main-project/sbt-template-project.g8

What is the correct way to generate the project out of the template?