If you are in a company that has multiple founders (with one of them wearing the hat of finance director, CFO, or something along those lines), then you are in an optimal situation, because they will know what the key financials will need to be. Most likely, you will find yourself in a position where you will need to have some hand in the finances. If this is the case, here are the key financial reports you should focus on curating:
Balance Sheet: This is the sheet that shows all of your current and fixed assets as well as shows you what your equity is in the business along with all liabilities.
Profit and Loss: This report is designed to show all of the income at the top, then all of the expenses. At the bottom, you will be able to see what your net income (or loss) is. One category that is worth considering is breaking down the expenses further into having a Cost of Good Sold Section. This can be very helpful in showing you how much it costs to create your product.
Budget to Actual: This report is helpful in showing how you are performing against what you had set aside in your budget. It can be extremely helpful in showing how your company is performing compared to where it should be at this time of the year.
Cash Flows: This report gives you an idea about the different areas in which your cash is flowing in the business.
Receivables Aging: This report shows how long current invoices are outstanding. This can be a very helpful tool in keeping track of invoices that are overdue. As a general rule, keep the aging on invoices to a minimum, with the focus on keeping your receivables as slim as possible.
Payables Aging: This shows how old your debts are. It can be particularly helpful in making sure you are not getting too far behind on bills, opening the door for interest and other penalties.
Those are the key reports that you should consider having. Of course, the time period can vary (monthly or quarterly reports) which would also dictate the closing that you would have.
One thing that is worth noting is that while the list above was given within the context of you being on your own and not having a dedicated finance person, being familiar with and understanding the significance of these reports is something that is worth having even if you do have a finance person on your founding team. This is because they will undoubtedly be presenting to the leadership team these reports for review. Therefore, having a clear understanding of what these reports are as well as what they mean will greatly reduce the effort that they need to put into explaining them, as well as will greatly enhance your strategy sessions with your team.
One key point that should be made is that depending upon the software used, you will be able to have additional metrics added (such as percentages). These additional analytical tools will help you gain further insight into what the reports are saying. Obviously, your finance person will have their own way of creating these reports, and you should definitely defer to them. However, if it is just you, then by all means experiment with additional analytical benchmarks. This will be particularly helpful since it will help you get the oversight that you need moving forward.
In conclusion, the level of familiarity and understanding that you require with financials will vary depending on the size and makeup of the founding team (you might even make hiring a finance person the first hire after you get started). However, one thing is crystal clear: you do need to be relatively familiar with the basic financial reports. The more you understand, the easier it will be to understand what is happening with your company.