If you have done basic financial admin you will have some understanding. A lot of it will be understanding the organisations processes, forms and definitions.
Many employees actively avoid anything to do with finance because they think it’s like maths at school. It isn’t, if you can +-/x and do % and use spreadsheets such as MS Excel you should be fine with the maths side. It also gives you and advantage in your career as understanding financials is something most people say they can’t do.
Preparing budgets , usually staff, non staff or projects which require you to understand the requirements for the next year/project duration. Normally you will have the last years/project budget as a starting point so it’s not a blank spreadsheet. Use this as your starting point reviewing last years budget against current spend and feeding in known changes for the next year. It’s your best guess as no one can predict the future.
Monitoring budgets is knowing whether you are on track I.e. do you have peaks and troughs in expenditure, if so allocate accordingly, Flag potential overspends early.
Make friends with your finance contacts and, rather than doing a training course where you will forget most of it, ask for the guidance and work through it logically as you complete the task. Ask your finance person if unsure and make a note of their advice.
Personally I have a tab on the spreadsheet called decisions where I note decisions I make on what to input so I can refer back. This is useful where you only do a task once a year or once a quarter.