Hi,

When you write a cover letter, try approaching it a little differently: closely examine the job ad and highlight/underline those verbs and qualities that you think you can be good at or could help the company excel because of your personality and skills (even if they're not based on professional experience). When you write the cover letter, indicate how your skills or personality traits would help you succeed in performing what they're asking for.

I would also include a sentence where you clearly admit that you do not have professional experience, but are enthusiastic and confident about succeeding in this job.

Always be honest, and if the volunteering experience is relevant to what the company is looking for, do include it as well highlighting the specifics that are relevant to this job ad.

Your resume/cv can remain somewhat generic, but always customize the cover letter to address what they're looking for.