How do I get to IIS Manager?
First of all, you need to check that the IIS is installed in your machine, for that you can go to:
Control Panel --> Add or Remove Programs --> Windows Features --> And Check if Internet Information Services is installed with at least the 'Web Administration Tools' Enabled and The 'World Wide Web Service'
If not, check it, and Press Accept to install it.
Once that is done, you need to go to Administrative Tools in Control Panel and the IIS Will be there. Or simply run inetmgr (after Win+R).
Edit:You should have something like this: 
You need to make sure the IIS Management Console is installed.
To open IIS Manager, click Start, type inetmgr in the Search Programs and Files box, and then press ENTER.
if the IIS Manager doesn't open that means you need to install it.
So, Follow the instruction at this link: https://docs.microsoft.com/en-us/iis/install/installing-iis-7/installing-iis-on-windows-vista-and-windows-7