Once you follow the instructions to install the coherence SDK package for Unity, you will be able to explore the package Samples with no additional download. You can either:
Go to: Coherence > Explore Samples
Open Unity's Package Manager (Window > Package Manager) and navigate to the package samples
Note that the Samples are meant to be self-explanatory, so they come with no documentation.
If, once imported the samples, the scenes show up magenta/pink, it's because the samples are made for the built-in pipeline and your project is using either URP or HDRP.
To fix this in URP, go to: Window > Rendering > Render Pipeline Converter
Click on the checkboxes to choose what to convert (Materials is necessary), then click the Initialize and Convert button. After a brief loading, you should see the example scenes displayed correctly.
For more information, refer to Unity's guides for URP or for HDRP.