I've written about Catan before. I've introduced people to Catan. I've reunited people with Catan. This is of course, t he physical, board game version of Catan, not the digital, Steam-powered version of Catan. Below you'll find the @steemgc write-up I did for Catan some time last year, where I compared it to the original tabletop version of the game. (Which - if you haven't played it before, is excellent).
You are attempting to settle new lands, and do so by placing settlements, upgrading them to cities, and collecting resources in order to do so, lumber, stone, sheep, brick, and wheat. You can only settle in two places, and often the tile out leads to you requiring multiple trading partners. You obtain resources by rolling the dice, and whatever number is associated to a resource, that you have a settlement or city next to, you get.
There's two dice, however, and the most common number you can roll is a seven. Seven means the robber is coming to someone's town, which lets you steal one of their resources, and block any additional production from that game tile until the robber is moved once more.
The video game version of Catan takes about the same amount of time to play as the board game version, if not a little quicker, on the basis that the AI doesn't take as long to think about things to do as humans do. It is well produced, and gets the game mechanics into a video game adequately, but it lacks the look of horror, disgust, and betrayal which is conjured by playing this board game as an actual board game.