Step 1: Go to the AcademicSoftware page for Microsoft Visio and click the green button 'Download MS Visio 2019' to download the .iso file.
Step 2: Open the .iso file by double-clicking. (You can also choose to unpack the file first.)
Step 3: Double-click on the file Setup.exe.
Step 4: Visio is now being installed. Once the installation's complete, the window will close automatically.
Step 5: Open Visio from your Windows Start menu.
Step 6: You will be asked to enter a valid product key to activate the program.
To get this code, go back to the program's AcademicSoftware download page. Click the green button 'Request' at the top right to get your product key. Copy-paste this key into the Visio window.
You can also use the program for 15 days without a license, or log in with your Office account to use an existing Office license. (Click 'Back' in the bottom instead of entering a product key to log into an existing account)
Microsoft Visio Professional 2019 is now installed and ready to use.