Use FitGirl or SteamRip. I also use SteamUnlocked which people say are unsafe but I've downloaded over 100 games from there and had no issues, so I won't recommend it but just adding my experience.
Also make backups to your PC using macrium reflect or other backup programs so you can restore from it in case you get viruses.
Do you know any subs good for asking the kinds of questions OP wants to ask?