build
In German, 'bauen' is the verb used to express the act of building or constructing something. It is a regular verb that follows the standard conjugation rules. For example, 'Ich baue ein Haus' means 'I am building a house'. The past participle 'gebaut' is used to express the completed action, as in 'Das Haus ist gebaut' (The house is built).
We are building a house.
This sentence uses 'bauen' in a present tense context. It applies to a situation where the speaker and possibly others are currently in the process of building a house.
They want to build a bridge.
In this instance, 'bauen' is used when referring to future actions, expressing a desire or plan to build something, in this case, a bridge.
He has built a boat.
The sentence demonstrates the past tense use of 'bauen', in this case in the form 'gebaut'. It means that the action of building has been completed in the past.