This is a regular verb. It follows the conjugation pattern of the verb hablar.
PresentPresente
El autobús tarda veinte minutos en llegar al centro.
The bus takes twenty minutes to get downtown.
PreteritePretérito indefinido
Tardé dos horas en terminar el examen.
I took two hours to finish the exam.
Negative ImperativeImperativo negativo
No tardes, la cena está lista.
Don't be long, dinner is ready.