Conditional expresses what happens if some condtion was met.

If I had a million dollars, I would buy a car.  (This is the imperfect subjunctive) This is the conditional.

In your place, I would fasten my seat belt.  En tu lugar, yo me abrocharía el cinturón.

It has the same irregulars as does Future tense.

The endings are added to the pre-existing -ar/ir endings.

I would like to buy tickets.  Me gustaría comprar boletos. (Polite requests)

They announced that the plane would arrive late.

Se anunció que el avión llegaría con retraso.

¿Dónde estaría Catalina?

Where would Catalina be?

You should confirm your reservation before going to the airport.

Deberías confirmar la reservación antes de ir al aeropuerto.

¿Les gustaría ir a la piscina sin salir de su casa?

Would you (all) like to go to the pool without leaving your house? (Literally, would it please you all...)