What knowledge does a system administrator need?

Question

System administration

Gentlemen, I need help!
I work as a specialist in information technology work in a state institution. I have responsibilities as a sysadmin, engineer, programmer, designer, etc.
I can manage my current job, but it is quite low level. Local network, file storage, joomla with a public template, PC selection on citylink, etc.
Recently, acquaintances offered to earn money, but offered to work for it. Work as a system administrator in the service station network. They talked about what needs to be done so that everything works without interruptions, and if there are interruptions, then remotely, or leave and identify the cause as quickly as possible and eliminate it. They asked about Radmins, Excel, telephony, video cameras, servers, the Internet...
The thing is, I know all this in theory. I set up the Internet and LAN at my current job, but with the help of routers, Wi-Fi and other collective farm devices. I did everything myself with the help of the all-knowing Google, an immense amount of time and a little bit of logical thinking, BUT! ..
A network of commercial service stations, where time is money. Everything is serious there. At least that's how I scared myself...
I really need help with support...searched several forums and resources for system administrators. But I'm afraid I won't be able to go to Google if there's a problem that I can't handle. I learn quickly, I grab too, but there are no acquaintances who could show / tell de facto, in practice. Maybe there are those who want to help get acquainted with the work of a system administrator? Maybe there are resources? Or maybe someone is ready to help on Skype, tête-à-tête, by phone?

Answer 1

You are not going to go to the system administrator, but to the "skilled enikey worker". An appropriate set of knowledge is needed - to understand everything as a person "who knows how to think and search in Google, and not click on the OK button and run to the helpdesk shouting everything is broken."
Ask what you need to do, read about it.
And so - Amy Nevet, LARTC (it gives good ideas about networks in general), the whole theory of DNS (not record types, but everything in general). If Windows - then look for a book on AD.
The good book about the organization of work - "System and network administration". There is not technical knowledge, but about how to organize your work.
Next - read about specific protocols, along with software that implements these protocols.