If you don't know how to write a cover letter, here's a very basic template:
Start: letter-style salutation. If you don't know who the hiring manager is, "hiring team" or similar is fine.
Introduction paragraph: who are you, what job this is, why you are interested in it
Paragraph 1: take one part of the job description and explain how your previous experience and skills would make you good at this aspect of the position you are applying for. This should involve a brief description of what you have done previously (in a job, in education, in volunteer work, etc.), not belaboring the point, and then how those skills apply. Talk a little about how those skills have helped you in a previous position while explaining those duties. This is also where you would explain if you have transferrable skills! Say you haven't worked in this exact field before, but you have skills (so-called hard skills OR soft skills) that apply to this position. This is where you convince the hiring team that these skills apply to what you are applying for.
Paragraph 2: basically the same as Paragraph 1, but with a different part of the job description. Try for something with a different skillset.
Paragraph 3: same as above. You don't need as many as three paragraphs. You can have as few as one. It all depends on the job and how much you have to say about it.
Closing paragraph: Conclude as to why you would be a good fit for the job. Thank the hiring team for considering you and re-emphasize why you want to work there. Sum yourself up in a punchy one-sentence conclusion. Sign off like a letter.
This should all be about a page of text, as the OP mentioned. It's not rehashing your resume, but explaining those skills, elaborating on them, and convincing the person or people reading these letters that you should be interviewed because you are a good fit. (Don't say that in so many words -- "I would be a good fit because...." but rather do it professionally, like "I would bring my passion for and previously strong results in teen literacy to [teen literacy librarian role]")
It's also okay to write a few basic templates for yourself! Just be very very careful to tailor them to each position, and don't accidentally send the template itself or the exact same cover letter to multiple places (or worse, the same place multiple times). (When I was most recently job hunting I accidentally sent a cover letter with the name of a different place because I copy/pasted and didn't proofread closely enough..... don't be me LMAO)
Cover letters aren't as scary as they seem, and people will actually read them. Search up some more templates if you like, and see if there are templates for your specific field, as well, since it might vary. Good luck job hunting out there!
