[Advice] How the fuck do I get a job.

I am currently one month away from turning 16. My family needs me to get a job as soon as I possibly can, for reasons I will not get into. The problem is, I have no clue what I'm doing. I understand the basic process, but I have no knowledge of the nuances of applying for a job. Even applying for a job made me incredibly nervous before, and though I have managed to submit a couple of applications by now, the whole process still seems to elude me. When am I supposed to make the follow-up call? What do I say in said follow-up call? Who do I ask for an application, the cashier? or do I ask for a manager? Do I need a resume, cover letter, etc. for a basic fast food or retail job? What would I put on said documents if I have no experience? Would anyone even want to hire a 15 year old who can't drive? It's not like I'm applying for any fancy place, I applied to Taco Bell and a grocery store, for God's sake. I have 10,000 questions, and no one I can ask. My mom only seems to get mad if I ask her for aid, because apparently everyone magically gains knowledge of these processes once they hit a certain age. When she does give me advice, it seems to only further convolute things. Why would I ask if a company is hiring after I apply? It just feels like there's so much I don't understand. Is there some base of knowledge everyone has innate access to? A class that I missed, or figure to ask that I lack? I apologize for the long-winded, unreadable rant, but it is a process that I require aid with, and the sub seems to be my best shot at getting up-to-date advice. Thank you for any answers.

EDIT: I would just like to thank the people who gave me advice, and also marvel at the fact that I recieved more clear cut advice in less than 10 minutes from mutiple people whom I don't know on the internet, than I have in a month from the people I know in reality. Thank you!