The two new destinations are DEN (an existing BA location) and MSP (which isn't [yet] serviced by BA).
2 new USA routes being announced 17/8 in Dublin
I would expect them to appear as codeshares on BA and bookable via BA.com and the contact centres, places like BDL do have a BA code, BA6163 in that case. Plus they will have at least 2 routes to being booked as redemptions, either directly on BAEC or by transferring Avios to Aer Lingus and / or Iberia. The one exception will be if there is a local restriction on the Joint Business Agreement, but I can't see either of these destinations triggering that. I would expect it to appear in a week or so.