One of the most important things to manage your personal finances, business finance or even just planning, is to be able to use excel for basic spreadsheets. Excel is a very valuable tool and using its functions can save you a lot of time (and errors) - Hands down, when it comes to planning, budgeting, making quotes etc... Excel is a piece of software we use daily. 

This video is a VERY basic introduction to Excel and how to use it to do some basic functions. If you do not have Microsoft Office, Google offers a free online version called Google Sheets which essentially works exactly the same. Get to know how to use Excel's simply invaluable!