Complex sentence: There will be a total of 26 singles in the A-Z Series, with an undetermined number of b-sides, with the single releases, not all will be radio singles, the ones that are radio singles will most likely be accompanied by a music video.
Split into simpler sentences: There will be a total of 26 singles in the A-Z Series, and an undetermined number of b-sides. Not all of the singles will be radio singles; the ones that are will most likely be accompanied by a music video.