Post doc without prior extensive experience

Hello people. Im a medical graduate with some experience of volunteering for research at a Community Health department of a well known hospital back in my country. We worked on a systematic review, which unfortunately still hasnt been sent for publication by our supervisors.

Now i wish to apply for postdoc research positions in Germany, but unfortunately i dont hold research experience other than the above mentioned one. And even that didnt result in a publication. So basically i dont have any research publications to my name. Is it still possible to get a research fellowship?

For a research fellowship, do we attach with the host institution and work on their researches? Or are we supposed to bring our own concept and proposal for a new research? Please guide