How to set up Open-XML-PowerTools

Question

I'm trying to use Open-XML-PowerTools. And I would like to execute it on powershell command line. However, I haven't got to the point where I can actually use it, because it seems that I could not have done the setup properly. So could you give me some advice ?

Things that I have done:

I tried to follow Build Instructions on the Github page. https://github.com/OfficeDev/Open-Xml-PowerTools/tree/master

1. git clone https://github.com/EricWhiteDev/Open-XML-SDK (master) under the directory : C:\Users\user\Documents\WindowsPowerShell\Modules

   And "Visual Studio 2019" directory exists at the location below :

   C:\Users\user\Documents\Visual Studio 2019

   So, sibling as "WindowsPowerShel" directory.

2. git clone https://github.com/OfficeDev/Open-Xml-PowerTools/tree/master (master) under the same directory as 1. i.e. C:\Users\user\Documents\WindowsPowerShell\Modules

3. open Open-XML-SDK.sln in the project directory "Open-XML-SDK" by Visual Studio 2019 (Microsoft Visual Studio Community 2019 Version 16.6.5). build the solution, then run "test all" from Test Explorer.

4. open Open-XML-PowerTools.sln in the project directory "Open-XML-PowerTools" by Visual Studio 2019 (same as above). build the solution, then run "test all" from Test Explorer.

5. start PowerShell ISE as administrator and make sure setting Set-ExecutionPolicy as Unrestricted.

6. from the PowerShell, put "Import-Module Open-XML-PowerTools". However an error arises saying,

 "Import-Module : モジュール ディレクトリに有効なモジュール ファイルが見つからなかったため、指定されたモジュール 'Open-Xml-PowerTools' は読み込まれませんでした。発生場所 行:1 文字:1 
    + Import-Module Open-Xml-PowerTools
    + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ResourceUnavailable: (Open-Xml-PowerTools:String) [Import-Module], FileNotFoundException
    + FullyQualifiedErrorId : Modules_ModuleNotFound,Microsoft.PowerShell.Commands.ImportModuleCommand"

where モジュール ディレクトリに有効なモジュール ファイルが見つからなかったため、指定されたモジュール 'Open-Xml-PowerTools' は読み込まれませんでした。発生場所 行:1 文字:1 means "because valid module file cannot be found in module directory, designated module 'Open-Xml-PowerTools' were not read, location of occurrence line:1 letter:1" in Japanese.