Yo-Yo Ma is the soloist in Prokofiev's Symphony-Concerto for cello and orchestra, and Andris Nelsons conducts Harbison's Koussevitzky Said, Rachmaninoff's The Bells, with the Tanglewood Festival Chorus, and a world premiere by Eriks Ešenvalds.(Some emphasis added.)
That page also has the schedule of concerts to be broadcast and streamed next week and over the coming season as well as links to some interviews.
I don't know why they won't list the pieces in the order they are performed. Harbison's piece opens the concert, followed by Ešenvalds and Prokofiev. Rachmaninoff follows the intermission, and concludes the concert.
The piece given its world premiere in the Thursday concert and its broadcast premiere on Saturday was titled "Lakes Awake at Dawn."
My recollection of the concert is that it was very good. The Harbison is brief, intended as a curtain-raiser, and quite amusing; the Ešenvalds sets the moods of the poetry well; and the Rachmaninoff is very stirring. Since all three of them have sung texts, it's an especially good idea to go to the BSO performance detail page and access the link to the program notes, where you can find the words. I think it will also be especially useful to read the notes on the pieces and check out the other background info.
The p/review I posted at the time has links to reviews. along with my impressions back then.
As usual, the concert is available by radio or webstream from WCRB on Saturday evening at 8:00 p.m. Boston Time (EDT). See the first link above. I recommend listening.