Install app

Directly go to this link: S: Contact Form - Contact Us to install the app.

After adding the app to the store is complete, you need to embed the app in the theme:

Go to Integrate Theme from the left sidebar -> Select the theme you want to apply -> Click the "Go to Theme Editor > App Embeds" -> Click the Save button in the upper right corner.

If you want to preview the application on an unpublished theme, then follow the same steps as above.