If you were starting a project from scratch you first need to have Unity 2019.3 to above. Select New Project from the Unity Hub, find and select HDRP Core. Name and select the file location before selecting Create Project.
For an existing project, the easy way to put it is you import your URP project assets into a new project. So you still need to create a new project as shown above.
- Find the Scene to be imported to HDRP
- Right Click/Left Click Export Package
- Name and Save
Now time to import into the HDRP Project.
- Assets/Import Package-Custom Package
Once you have it imported you will notice everything looks pink. That will be fixed by going to Edit/Rendering/Materials/Upgrade All built-in Materials to HDRP.
As far as I know, if you bring in a URP project you will need to go to every material and convert it to HDRP lit. If you bring it in as Standard Pipeline the entire project should convert to HDRP. I brought mine in as URP and had to convert all the material plus re-set all the textures.
Once you have the assets in HDRP you can tell the difference. As of now I still have some textures to reset before moving forward but I can show you a side-by-side of URP and HDRP. I took simple screens for the outside walls.
Now that I have my project Unity HDRP I just need to make sure all materials are ready then continue learning more. I will write more about HDRP as I go. Have a good day.