They don’t teach how to use a spreadsheet in school, but nonetheless it is expected that all entrepreneurs have that skill. In case you don’t, there are online tutorials to get you up to speed.
Video Tutorials for Absolute Beginners
Some good YouTube videos for spreadsheet beginners:
By far the most popular spreadsheet is Microsoft’s Excel. Microsoft’s tutorial can be found here.
If you don’t own a copy of Excel, or if you prefer to use a spreadsheet that can be edited by anyone on your team and viewed by anyone on the internet, the most popular choice is Google Sheets. Google’s primer on their product can be found here. It’s not for absolute beginners, nor is Zapier’s more comprehensive tutorial here.