As you probably know, chessable contains an enormous amount of courses. To find the best fit to your need (here adding the Rossolimo to your repertoir) I would go as follows:
- Go to chessable > Tools > Opening Explorer.
- Insert your position of interest and hit "Search courses for Position":
- A list of the available courses that include this position will appear:
In your case, make sure that it is a repertoir from White perspective. I would go for "Keep It Simple: 1. e4 - 2.0". Here is what the cover of the course says about the Sicilian:
♚ Take Black’s tactics out of the Sicilian. With the Rossolimo and Moscow variations with an early Bb5, you’ll disrupt Black’s usual tricks and set up a dominating center…or an endgame Black will hate you for