Save your files and you verify there are no compilation errors.
Create a test file
Go back to your site root and create a test file by selectingFile > New > File
Enter a name and select the template you just created.
Select a workflow and select Create.
Double click to open in Preview mode. You will see a message letting you know to switch to Inline Editing Mode to enable Drag and Drop
Select Inline and the available zone will be visible in your test page. In the Blocks panel, the available content blocks will turn blue.
Drag some blocks into the zones. You can also drag images from the DAM panel into the page.
Save to confirm the template is implemented properly.
If you don't see the message in Preview mode or content blocks do not turn blue, the drag and drop functionality is not active. To trigger, Force Reload from the refresh button in the left corner of the workspace.
If you see an error when saving your test page please note that as of May 2018, templates with drag and drop zone are only supported in site root folders at the root of your CMS instance. Templates with drag and drop zones created in nested site roots will see an error when saving, so the error may be related to the location of your site root folder.