Clinic question

I work at in community mental health, we recieve little to no guidance and this is very different from any other nursing job that I have had in the past where rules/policy/regulations were VERY important. I know the revolving door of DONs and nursing supervisors is not helpful but anyhow, recently we came into a situation where a community health clinic wanted to send us a patient to do an injection on, it would be a 1x visit for an injection, the client would not have seen our MD. Our current DON was not comfortable with it since they are not a patient of ours and I basically follow her lead because she's my supervisor. What needs to be in place before this patient can receive an injection? Obviously doctor orders but can we follow another doctor at a different clinics orders or do they need to see our doctor first since we'd be administering medication? We also have electronic records to a certain capacity (it's an old system and not completely EMR) we still have charts to document in also.... where does the documentation come into place if this person isn't in our system and can only be put in "contact" status if they don't do intake process..... so many questions and I just want to do what is right. Help.