How do I run IIS Express from command line?

Make sure you have installed it on your machine by checking C:\IISExpress /?

Then you can access using the command line.

Please refer to this document:

https://docs.microsoft.com/en-us/iis/extensions/using-iis-express/running-iis-express-from-the-command-line

What are the differences between IIS and IIS Express?

 There are a number of differences. 

Here is a table I extracted from the Microsoft website:

Can I manage IIS Express in IIS Manager?

 The simple answer is no. 

IIS is managed by IIS Manager and appcmd.exe

IIS Express is managed by Appcmd.exe

IIS Express Management tasks are built into:

WebMatrix

Visual Studio 2010 SP1 and later versions