Umbraco is a Content Management System (CMS) built on legacy ASP .NET (i.e. not .NET Core, and therefore Windows-only). A couple of months ago, version 8 was released, with breaking changes and some new features. In this article, we’ll see how to quickly get up and running with Umbraco 8.0.1 and Visual Studio Code.
Downloading Umbraco
The first thing to do is grab the Umbraco starter kit from the download page. At the time of writing this article, the latest version is 8.0.1.

Beneath the download link, there’s another link to the installation guide, which are mainly the steps we’ll be following in this article (despite the warning that it may not be updated for v8). Unfortunately, the “getting started” link further below (not shown in the screenshot above) is broken.
After downloading the Umbraco zip file, extract it to a folder of your choice.
Running Umbraco with Visual Studio Code
Visual Studio Code is a recent (compared to Visual Studio) cross-platform Integrated Development Environment (IDE) developed by Microsoft, and can often be used as a replacement for Visual Studio. Download Visual Studio Code if you don’t have it already.

After running Visual Studio Code, use its “Open folder…” option (via the start page or the file menu) to locate the folder where you extracted Umbraco to.

Then, install the IIS Express extension for Visual Studio Code by following the steps illustrated in the above screenshot.
With that done, hit Ctrl+F5 to run the website. Be patient, as it may take a little while to load the first time.
PageInspector.Loader Assembly Issue

If you also have Visual Studio 2019 installed, then you might run into a problem that displays the above error instead of the website.
If this happens, locate the C:\ProgramData\Microsoft\VisualStudio\Packages\Microsoft.VisualStudio.AspNetDiagnosticPack.Msi,version=16.0.12311.10635 directory, run AspNetDiagnosticPack.msi, and hit Repair. After running the website again, it should work.
Installing Umbraco 8
After a little wait, the site should load and you should see the setup wizard:

In the first screen (shown above), you give it your name, email address and a password. Then, you can choose whether to hit Install (which installs Umbraco with default settings, including an SQL Server Compact Edition (SQLCE) database), or else Customize and choose the options you want for the setup.
The installation itself will also take a while, but when that’s done, you’ll be redirected to the Umbraco CMS (which you can reach at any time via the /umbraco URL).

You can log in using the credentials that you supplied during the setup.

Inside the CMS itself, you’ll get a quick tour of how the page layout is organised. If you’ve used Umbraco 7 or prior, you’ll notice that some things have been reorganised – for instance, the Developer section has been merged with the Settings section.

At this point, you can go ahead and start creating content. As you do this, you’ll see your changes reflected in the Umbraco Sample Site, which you can access by going to the root (/) of the website URL.
Thank you for taking the time to put this together. Correction: Umbraco 8 is not installed on “legacy” Asp.net, it is using the latest Asp.net framework. Asp.net Core is different in that it can be installed on other (than Windows) hosting; that does not make the Asp.net framework legacy.