I found this note and I couldn't figure it out. How can I play D flat 3 beats when I got in the last beat another D flat? The last one interrupt the first one that why I cant play the first D flat All the three beats. If you have answer please let me know
Those are intended as two separated voices, and it's common for keyboard instruments (but not only) to have to play "again" a note that is theoretically still playing in another, and that's also for historical reasons: it was common to have a keyboard instrument with more than one keyboard.
Consider this excerpt from the second Praeludium of the first Well-Tempered Clavier book (note the C on the top staff):
That's to be intended more as musical coherence (that voice should play for the whole bar), than "key consistency".
Also, writing your example in a "correct" way would have made the score more cluttered, without any real benefit.
So, just play it again after releasing it as late as possible.