I purchased a copy of Terraria on steam about a year ago to play on my windows laptop. I switched over to a different PC with Linux as its operating system.After downloading Steam,Steam only downloads the windows version of the game.After referring to the internet, I got to know about the Terraria Mac and Linux open beta which is supposed to be an option in library>Terraria>Properties>Betas which does not exists and shows only one option called OPT OUT OF ALL BETA PROGRAMS. I've tried Wine and PlayOnLinux but both don't work for me. Any help?
Install the Steam client for linux that best suits your distribution (latest version found here) and make sure it has all prerequisites to run.
Start the steam client as your regular desktop user and sign in to steam using your steam credentials.
If the game you want to play is supported by steam under SteamOS/Linux, it should be marked as such in your library and you'll be able to install it the usual way. (Terraria is marked as such so you should be good.)
Enjoy your game.