I can't compile JetEntityframeWork

Question

I wanna use the MS Access database as DbFirst in my project using JetEntityframeWork. I try to enable DbFirst according to the installation guide of JetEntityframeWork here, but I can't.

this is my steps to enabling:

1. Download JetEntityframeWork v-6.2.0 source code from here.
2. Extract the zip file
3. Open my Visual Studio 2019 as Administrator and open the solution
4. Update "Install.cmd" (REGROOT) => "SET REGROOT=SOFTWARE\Microsoft\VisualStudio\19.0_Config"
5. Compile the project enter image description here.

It return me an error enter image description here.

Error1 : Severity   Code    Description Project File    Line    Suppression State
Error   CS0006  Metadata file 'C:\Users\MyUsername\Desktop\123\JetEntityFrameworkProvider-master\Debug\JetEntityFrameworkProvider.dll' could not be found

Error2 : Severity   Code    Description Project File    Line    Suppression State
Error       The command ""%ProgramFiles%\Microsoft SDKs\Windows\v8.0A\Bin\NETFX 4.0 Tools\gacutil.exe" /u "JetEntityFrameworkProvider"" exited with code 3.

Did I forget anything? What should I do now?