Kexi is designed to serve both beginners (when it comes to databases) as well as more advanced users who know a great deal about databases. If you belong to the latter group, you will probably want to skip the sections of this documentation you are familiar with. However you will surely benefit from reading chapter 2.4 intended especially for experts.
If you have only used spreadsheets for data processing so far, you should read chapter 1.2. Database and spreadsheet. If you feel that while using spreadsheets some activities, like entering the data, are too tedious and time-consuming, and final result contains hard-to-find errors, then Kexi could be a good solution for you. Even if you use only a small part of functions provided by Kexi, your data stored in a form of database will probably be more legible and easier to comprehend for your coworkers.
If you have previously used applications with a graphic user interface (which is highly probable), using Kexi should be easy since it is in many ways similar.