Verb conjugation of "concentrar" in Spanish

I ordered a cab at four o'clock in the morning which took me to the Central Bus Station. I was much to early because the bus would go just at seven o'clock. Anyway I was sitting there and listening to music.
Other tourists needed to check out first before others could check in. I wanted to see the ruins on the same day and booked a tour in this little jungle settlement and waited for the tour guide.
We took many images and stayed there for over three hours, just enjoying the view. We finally went back to Kowloon with the subway, where we went to eat Sushi in a vivid, dynamic restaurant.