How to add a template to an isolated shell

Question

I work with Microsoft Visual Studio (2015) sandbox. I want to add my own created template.

What I have already done:

1. I created a new isolated shell project (File → New Project → Other Project Types → Extensibility → Separate Visual Studio Shell)

2. I created a template as a .zip file (File → New project → Visual C # → C # project template → Add items (files and folders) → Export template

3. This .zip file that I added to my isolated shell (.vsixmanifest → Assets → New)

If I debug my project, I cannot see that my project in an isolated shell is just an empty solution.

How can I make my template visible?

Thank you in advance