How to add a UI to a WiX 3 installer?

Below is a link to a good example on how to custimize the WixUIExtensions.

Customised UIs for Wix

If you use the .wixproj directly via MSBuild, without Visual Studio, the required modification is to add this:

<Project ...>
  ...
  <ItemGroup>
    <WixExtension Include="WixUIExtension">
      <HintPath>$(WixToolPath)WixUIExtension.dll</HintPath>
      <Name>WixUIExtension</Name>
    </WixExtension>
  </ItemGroup>
  ...
</Project>

See Re: (WiX-users) How to get off the ground with WixUI_Minimal?

The wixui extension is no longer wixui.wixlib. It was rolled into the WixUIExtension.

If you are on the command line, add -ext WixUIExtension to the call to light.exe.

If you have a WiX project in Visual Studio, add a reference to "WixUIExtension" by right clicking on "References" in the Solution Explorer.

See the WiXUI Dialog Sets page for WIX3.