How far do they go?

No matter where in the world you play bridge, you are entitled to certain basic guarantees. Clubs are worth 20 points a trick, the opening lead is made by defender on declarer's left, and aces always beat kings. The laws don't say how many boards make up a session. They don't require you to use high-card points as the basis of hand evaluation.

In short, the Laws specify the the mechanics of how bridge is played, and tell the players and directors what their rights and duties are. They specifically leave open-ended the details of how a tournament is run, and in Law 80 they invite sponsoring organizations ( the ACBL, or the management of your favourite online bridge site, or the owner of your local club) to announce "regulations supplementary to, but not in conflict with, the Laws."

The Law book is, in that respect, much like the Constitution of the US: it specifically permits and forbids certain things; but within those boundaries, it leaves lots of freedom. The "supplemental regulations" that apply in the ACBL, for example, are in a book some three times the thickness of the Laws themselves.

Some specific examples of things the laws do and don't control:

Bidding systems:

In general, the Laws guarantee you the right to make any natural bid at any time, but allow the sponsoring organization to place whatever limits on conventions that they choose. For details see the systems section of this page.

Alerting rules:

The Laws require that your system be fully disclosed to your opponents. But exactly how this is done - convention cards, alerts, announcements, answering questions - is each site's own choice.

Handling misexplained bids, resolving contested claims, scoring unplayable boards, etc.:

The Laws specify exactly how this must be done. The rules for online games are the same as they are in all the bridge clubs in the world. Similarly, the penalty for a lead out of turn or a revoke is exactly the same anywhere in the world.

The form of scoring:

The Laws tell us what each contract is worth, and what IMPs, matchpoints, and total-point scoring are, and how to score games using those forms of scoring. However, they also say that a sponsoring organization can use some other form of scoring (cross-imps, Butler IMPs, IMPs converted to Victory Points, etc) if they choose. In particular, rules about how ties are broken and to whom masterpoints and prizes are awarded are left entirely to the sponsor to set.