A spreadsheet - in the most basic sense - is a grid that contains data. The current convention is for spreadsheets to have numbered rows and lettered columns.
While spreadsheets may seem intimidating upon first look, they really are easy to learn.
One of the most useful elements of spreadsheets is that they are as "small" or as "big" as you like. When you start up a new spreadsheet workbook, you see a huge number of cells, yet it is possible to use only a few cells to create something useful to you. Don't be inimidated by the initial size of the screen - think about what it is you are trying to do and how much space you will need to do just that!
As you develop your knowledge of spreadsheets, you will find them useful tools for storing lists, sorting alphabetical data, sorting numerical data, performing calculations on numerical data, and modifying text. If you don't know why you would want to do some of those things yet, do not worry - you may never have a need to do any of those things. As mentioned earlier, spreadsheets are wonderful in that you don't have to use all the space and/or functionality they have available - you only have to use them to do what you need to do! The key is in finding out what spreadsheets CAN do, and how that can be useful to you!