The Project Template Stitching feature allows you create a new Project from an Opportunity by "stitching" (combining) different templates associated with Opportunity Products.
Please note: To use this feature, please make sure you've completed the necessary configurations. See help article on "How to Enable the Project Template Stitching Feature".
Since the Project Template Stitching feature allows you to create a single Project by combining different templates related to Opportunity Products, the first step would be to create your templates.
If you are not familiar with how to create Templates in Inspire Planner, please refer to this help article: Project Templates.
After you've created your templates, you will now need to map them to Opportunity Products. What you're doing is essentially defining a template to be used for each Opportunity Product.
Now that you've specified which templates are to be used for each of your Products, you can now create new Projects from Opportunities by "stitching" (combining) templates that related to the Products for your Opportunity.
Please make sure that you've already added the Products to your Opportunity.
It is always best practice to then review the new Project that was created. A few things you should consider reviewing and adjusting: