Navigate to the Downloads page on the Unity website and download Unity Hub for your operating system.

After Unity Hub installs, open it and select the most recent Long Term Support version of Unity to install.

Go to your Unity installation in Unity Hub and click on the settings cog wheel. Then, click on Add modules to view the available modules for download.

Under Dev Tools, check off Microsoft Visual Studio Community 2019 and then click Install. This will install Visual Studio, which you'll use to edit C# scripts in your Unity program.

After installing Visual Studio, go to the Visual Studio Installer window and click on Modify next to the Visual Studio 2019 instance.

Under Workloads, navigate to the Gaming section. Check off the Game development with Unity option. Then, click Install.