Samples are provided by pipeline, if you want to import the samples please use the "Start Screen" to do so instead of unpacking manually, this will ensure that they are imported correctly. Go to Windows > Amplify Shader Editor > Start Screen and under "Shader Samples" select the ones you want to import. Do be aware that importing any SRP samples requires to first install the respective pipeline using the package manager.

However if you still want to import them manually here is the breakdown of the included packages:
    * "Sample Resources": constains the assets shared between all pipelines, like textures and meshes, this should always be imported first
    * "Built-In Samples": contains the samples shaders with their scenes for the built-in rendering system
	* "HDRP Samples": contains the samples shaders with their scenes for HDRP 7.X.X and up (Unity 2019.3 and up)
	* "HDRP Samples (Legacy)": contains the samples shaders with their scenes for HDRP 6.X.X and down (from Unity 2018.2 to Unity 2019.2)
	* "URP Samples": contains the samples shaders with their scenes for URP 7.X.X and up (Unity 2019.3 and up)
	* "LWRP Samples": contains the samples shaders with their scenes for LWRP between 4.X.X and 6.X.X (from Unity 2018.3 to Unity 2019.2)
	* "LWRP Samples (Legacy)": contains the samples shaders with their scenes for LWRP 3.X.X (Unity 2018.2)

Please notice that in some cases the sample may have been created in a different version from the SRP that you are using which can produce "pink" shaders. If that happens it's usually the case that you only need to open the shader in ASE and save it to update it.
