How to invoke exe using custom action in WIX V4?

Question

I have created installer(.msi) using WIX Toolset V4.Added files that gets copied to destination when msi file is invoke. I am also copying dependency(DirectX redist exe) for the application. I want to invoke that DirectX while installing the application itself. How do I do that?

I have tried invoking using custom action in WIX v4 toolset, but nothing happens. Below is the code snippet that I have used:

<Component Id="DirectXExe" Guid="GUID">
    <File Id="DirectXExe" Source="C:\Unity Projects\directx_Jun2010_redist.exe" KeyPath="yes" Checksum="yes"/>
</Component>
</Fragment>
    <Fragment>
        <CustomAction Id="InstallDirectX"`your text`
                      FileRef ="DirectXExe"
                      ExeCommand=""
                      Execute="immediate"
                      Return="ignore"/>
        <InstallExecuteSequence>
            <Custom Action="InstallDirectX" After="InstallFinalize">
            </Custom>
        </InstallExecuteSequence>   
    </Fragment>