Essentially, successfully incorporating an opening into your repertoire involves:
- knowing the standard positions you want to reach
- learning the main variations that lead to those standard positions
- learning about the positional concepts that are relevant
- learning about the common tactical motifs that arise
- being aware of the strategic plans to carry out
- studying a set of illustrative games
These days, fortunately, a lot of opening repertoire books (as opposed to reference works) are available, reducing the workload required to learn a new opening system.
One thing to bear in mind though is the need for flexibility:
"a player normally strives to create middle game positions which suit his personal tastes and style, but since the opponent fights against this it is not always possible to get one's way and it is useful to have reserve objectives" Kan, From the Opening to the Middle Game
Whilst positional concepts such as 'the French bishop' may persist throughout most variations of that opening, in other strategically rich openings the nature of the game and the concepts to understand can vary widely depending on the lines your opponent chooses. These four positions, for example, all arise from the same opening , the Sicilian Kan Variation, but have radically different characteristics:
Don't expect to learn all the ideas overnight, get comfortable with concepts from one or two positions in your chosen opening and then start to play it, gradually incorporating more depth and breadth into your understanding.