What I will say is that you'll likely need to set with someone or read some documentation (if they've created any) on the expected use of Salesforce. Every company is different but in a BDM role, you may enter things like your appointments (meetings and calls), track your contacts by entering leads or updating contacts, create notes regarding interactions, you may even open opportunities for prospects and pass to sales (depending on what the business does).

Sometimes your admins or consultants will create other processes and ways for you to use Salesforce so part of the process will be learning what items your company puts value on.