If you’ve never had any experience with a sous vide the best thing to do is read around the subject as much as possible - understanding the science behind it is pretty key and half the fun!
Then start off with a few cheap & easy recipes (I don’t recommend diving straight into 72 hour short rib or a £100 porterhouse steak). Try these recipes: cod, poached eggs, hollandaise or sirloin steak for a low key start.