...
First of all - you need the Template created. Read how to do it here
Step 2: Accessing Templates Management
Then navigate to the created Template following this instruction
Step 3: Setting the Scope
...
Choosing Projects Scope: Choose “Selected Projects” option if the template is intended for a single or multiple projects
Selecting the Project: Use the “Projects” dropdown menu to choose the project(s) where this template will be used.
Implications: A project-specific template is visible on Create from Template popup for the chosen project and accessible only to users who have “create issues” access to the selected project while creating a new issue from the template or applying the template to an existing issue.
...
Step 4: Finalizing Your Template
...