A young person who is interested in Catholic meditation asked me for an example. The Gospel of the day in America yesterday was the chasing of the money changers out of the Temple in Jerusalem. Now, St. John places this immediately after the Wedding Feast at Cana, placing it at the first passover in his gospel and at the beginning of Christ's public life, while the synoptic writers place it after the Entry into Jerusalem, Palm Sunday, the beginning of Holy Week.
In a meditation, one imagines or places one's self in the scene, but the Holy Spirit may indicate some knowledge regarding the meditation which is personal. For me, in meditation, the Temple was revealed as my soul and my body, and the money changers are the unsavoury desires of my heart for worldly things. One can give up all for the sake of Christ, but still have the internal desires. God has to purify my heart, and mind, and soul so that I no longer desire anything but Him and His Will. That would be an example of a meditation based on Scripture.