There is wide latitude on the types of instruments awarded as a result of a Broad Agency Announcement (e.g. Grants, Cooperative Agreements, OTAs, etc.) for purposes of this question I will assume you are awarding a FAR based contract.
The guidance can be found at FAR 15.509 and DFARS 253.213 depending on your scenario. In many instances the SF 26 Award/Contract is used because many BAAs do not use a form (SF-33) as the solicitation method, see FAR 15.210.