1) Navigate to File Management (Admin > File Management) 
2) Modules > Add New Module > Digital Asset Management
3) Module > Settings > Module Title (File Manager) > Save

Watch the video below to quickly import portal template on your DotNetNuke site.

Or follow the below steps:-

Step 1

You will need to increase the executionTimeout to 900 in web.config as below:-

httpRuntime shutdownTimeout="1200" executionTimeout="900"
useFullyQualifiedRedirectUrl="true" maxRequestLength="12288"
requestLengthDiskThreshold="12288" requestValidationMode="2.0"

Step 2

Copy portal template files to Root/Portals/_default/.

Step 3

Admin > Site Wizard > Next > Select "Dixit" template > Select "Replace" radio button > Next

Step 4

Select "InnerHtml" skin and "Title_h4" container for your template.