I am extremely new to mojoportal and setting up any kind of SQL Database and I'm also very very new to managing and configuring IIS.

I tried to use the Web Platform Installer by following the directions here: https://www.mojoportal.com/installing-mojoportal-using-the-web-platform-installer, but I received an error when I tried to install the SqlLite version.  
I'm using Web Platform Installer 5.0 and the error I received was this: "This product did not install successfully: Downloaded file failed signature verification and may have been tampered with".

Since I couldn't use the Web Platform Installer, I tried to install my self by following the directions here: https://www.mojoportal.com/iiswebsetup.aspx.
I created a virtual directory under my 'Default Web Site' in IIS Manager. I named it mojoportal and I pointed it to my D:// drive where I have a folder called mojoportal and inside it is the downloaded wwwroot folder for SqlLite.  I didn't see the virtual directory underneath 'Default Web Site' so I tried adding it again, but I got an alert saying that it already existed, so I must have added it.

I tried to follow the next set of directions to give mojoportal read/write access by editing permissions on the folder.  I opened up properties -> Security clicked 'Edit' and then clicked 'Add'.  I tried added 'ASPNET' but I got the following error: "An object named "ASPNET" cannot be found. Check the selected object types and location for accuracy and ensure that you typed the object name correctly, or remove this object from the selection."  I have no clue what this means.

I'm stumped as to where to go from here especially regarding how to set up SqlLite with both mojportal and my ASP.NET MVC Core application.  I simply just want to be able to create a ASP.NET MVC Core web application with mojoportal installed on my local machine so I can create my website and then publish it to my hosted server.  The instructions are not clear for someone as new to this as I am.

Can any one help me out?