1) Open the Packages Manager window (Windows -> Packages Manager)
2) Downloading and importing High Definition RP
3) In the Render Pipeline Wizard window that opens, click the Fix All button
4) In the Create or Load HDRenderPipelineAsset window that opens, press the Crete One button
5) Select the material in the Materials folder for example the Ground material and click the Edit button
6) In the ShaderGraph window that opens, select the MasterNode and activate the Graph Inspector
7) In the Graph Inspector, in the Target Setting menu, click the + button and add HDRP
8) For vegetation materials, additionally enable Alpha Clipping in the Graph Inspector
9) For water materials, in addition, in the Graph Inspector, change the Surface Type to Transparent
10) Click the Save Asset button
11) In the HDRPDefaultResources folder, select DefaultSettingsVolumeProfile and disable everything except Shadows and Tonemapping in the Inspector
12) Project updated to HDRP
