This article will cover both how to install Unity for the first time, and how to install new versions of Unity for pre-existing installations. Before installation you may wish to review Unity's system requirements.
First Time Installation Only - Unity Hub
If you're installing Unity for the first time, the first thing you'll need to do is install Unity Hub - which helps keep track of all your projects and Unity versions. The steps below will describe the process for installing Unity Hub. If you already have Unity Hub installed, feel free to skip to the next section.
2. Click on the big blue "Download Unity" button on the front page.
3. Download the version of Unity appropriate for your machine. In general, this should be auto detected and available via the big blue button. If it isn't, you can easily select the "Download other versions" button to find the version right for you.
4. Open up the installation file and follow the installation steps (which will simply have you accept the terms and pick a location to install Unity Hub).
Installing a Unity Version
Whether you're a first time installer or a previous user looking for a new version of Unity, the installation of Unity follows the same steps described below.
1. If you haven't done so already, open up Unity Hub.
2. From the left-hand menu, select the Installs tab.
3. On the Installs page, select the "Install Editor" button in the top-right.
4. The Install Unity Editor page should pop-up. From here, you should select which version of Unity you want to install and hit the "Install button". In general, we recommend installing the latest LTS (even if it is different from the screenshot below).
5. The next step is to select the modules to install along with Unity. There are several options, including build supports for different platforms, language support, and so forth. You should select the modules most relevant to you, but note that you can install these later at anytime.
However, if this is your first time installing Unity, make sure to select Microsoft Visual Studio Community. This is the default IDE required to work with code in Unity. For previous users, you should see it mentioned as already installed.
Once you've selected everything, hit the Install button in the bottom right to start the installation process.
6. Wait for Unity to install. Note that because of the file size, this may take some time. Once installation has finished, though, you can start using your version of Unity!