Create an "Hardware Platform Specification Project" "reference-TE0300_hw_platform"

You should click "File" >"New" > "Project"

Xilinx SDK New Project

A pop up "New Project" will appear.

Click "Xilinx">"Hardware Platform Specification", then click "Next".

Xilinx SDK new HW Platform Specification

A new pop up "New Hardware Project" will appear

Xilinx SDK HW Project New Wizard 1

Under "Target Hardware Specification" click "Browse..." button.

A new pop up "Hardware Specification File" will appear.

"Hardware Specification File" pop-up

Select "system.xml", "C:\XilinxProject\reference-TE0300\SDK\SDK_Export\hw\system.xml"

After the selection a new  hardware specification (with name "reference-TE0300_hw_platform") appears in the Procject Explorer of SDK.

Reference HW platform