Build your repertoire around the decisions you expect to face. Select a main first move as White, an answer to 1.e4 as Black, and an answer to 1.d4. Then map the common branches that prevent your preferred setup. This produces a useful coverage checklist: what will you do when the opponent exchanges early, advances a central pawn, or chooses a different development scheme?
Keep the initial set small enough to revisit. A repertoire containing hundreds of unchecked variations is difficult to use over the board. For each selected line, know the opening idea, one tactical danger and a likely middlegame plan. Depth should follow need: a forcing tactical sequence deserves more precise preparation than a quiet position with several reasonable developing moves.
The London, Caro-Kann and King's Indian form the site's starter selection. Treat it as a convenient starting set rather than a complete answer to every opponent. You can remove lines, choose different openings, or add specific branches. In particular, look separately at unusual first moves and move orders that steer away from the named opening.
After each playing session, locate the earliest unfamiliar decision. Decide whether it belongs in your repertoire and add a short explanation if it does. Revisit that position through recall practice instead of repeatedly browsing the whole catalogue. Your repertoire should grow from games you play and positions you understand, with enough stability that earlier study continues to help.
Try this at the board
Choose one White opening and two Black defences, then identify a reply that each choice does not yet cover.