I have applied for retail seasonal jobs but haven't heard back after applications / interviews at the moment. I am low on funds and need a job to get through the next few months. Today, I showed up to a seasonal business and asked if they were hiring, was hired on the spot without questions asked, and told to show up for a shift tomorrow. I tried to let the manager know about my availability, but they weren't interested. The business operates 7 days a week, so I'm presumably expected to have open availability for all of it.
The manager walked away into their office before I had finished asking questions. The place is loud, so when I knocked the open door, they didn't hear. I stepped in to ask about pay. They said it's minimum wage with unspecified benefits, and got very upset that I walked into their office. They told me nobody is permitted to do that, that I asked too many questions, to leave now, and show up tomorrow if I want work. There was no contract to sign.
I need money. I don't know if I can handle 14h/7d availability, but it's a job that wouldn't last longer than 1-2 months. Should I show up and take it as far as I can? I'm worried that at some point if I can't take on the next given shift, they would fire me on the spot and refuse to pay me for any of the season's labor. It's my first job, so I'm asking on your experience on whether these are red flags, or if I'm being too paranoid about this hiring.
If there is no contract and shifts are allocated via word of mouth, how do I legally document the hours I worked to ensure that I get paid for all hours? I live in California in case people want to cite local labor law.