A word about the different .NET Software versions
The software you need is free from Microsoft, and is called Visual Studio Community 2017. You can get the software from here:
Download page for Visual Studio Community Edition
Microsoft do have a habit of changing this page. But you're looking for the Community 2017 edition. At the time of writing, have a look for a link in the top right that says Free Visual Studio. If they have removed the link, click on Products, then Overview. On the Download Visual Studio menu, select Community 2017.
Once the download starts, you may see a box appear. Make sure to select the same ones as in the image below:
We have selected Net Desktop Development in the main area, and SQL Server Express 2016 on the right. (You only need SQL Server if you're going to be doing the database section in the book version.) Click Install when you've selected the correct options.
If you have an older computer and operating system, you may still be able to download the previous versions of Visual Studio. Click on the link below, then scroll down to "Express for Windows Desktop".
Whichever version you get, the download will be quite large, so may take you some time, depending on your connection speed. It's a great piece of free software, though, and means you can do our full course without paying any money!
Unfortunately, we can't answer questions about the installation.