When did the ottomans try to invade Europe and how many times did they try to invade Europe? who were the rulers at the time?

The Ottoman wars in Europe were a series of military conflicts between the Ottoman Empire and various European states dating from the Late Middle Ages up through the early 20th century.

But I would tell about the main one which change the face of Europe.

1453 - fall of Constantinople that was a great start to conquer Europe.

The attackers were commanded by the Sultan Mehmed II, who defeated an army commanded by Emperor Constantine XI Palaiologos and took control of the imperial capital, ending a 53-day siege that began on 6 April 1453.