Cannot get this sample to build...any ideas?

Multiple occurences of the following two errors are stopping me from playing the FPS Sample.

Packages\com.unity.entities\Unity.Transforms\TransformSystem.cs(450,55): error CS0117: ‘float4x4’ does not contain a definition for ‘translate’

Packages\com.unity.entities\Unity.Transforms\TransformSystem.cs(677,46): error CS0117: ‘float4x4’ does not contain a definition for ‘scale’

I’ve reimported the prefabs, the models and goorifle and goorocket…I’m on 2018.3.0b7 - I’ve taken it off the Perforce setting to Visible Meta Data…

What else do I need to do? Any help welcomed. (BTW I’m not a programmer, I was just wanting to take a look at it)

You need the older Unity.Mathematics library.
Check if your packages.manifest matches.
FPSSample uses custom Entities and HDRP package.