Level and denomination
A bid combines a level from one to seven with a suit or notrump. The level counts tricks above six. At one level, the denominations rise clubs, diamonds, hearts, spades, notrump.
An original exercise
Choose a bid in the ladder above, then say its denomination and trick target in separate sentences. Change only the denomination, then only the level. Notice which part of the description changes.
What the diagram does not say
A higher bid is not necessarily a sensible call. The display does not interpret a system, assess a hand or decide the legality of a double in an auction. Those questions need the full context and your partnership agreement.