You're not going to be able to do everything in one day. Somethings may be more difficult and take more time than others. Some things you may not understand at all. If you want any sort of privacy at all, do something, start somewhere.
If you're still using Microsoft Windows, stop. Linux desktops have become easier and better looking in the last couple of years. Linux should be the number one choice on this list, but it takes some time may not be as easy for everyone.
If most of your computer use is email and web browsing, moving to Linux will be easy. If you think you're stuck in Microsoft Office, you're not. Libre Office is a compatible, full featured substitute.
Almost every program has a Linux replacement Adobe Presenter and any adobe program and Microsoft Visio are the only programs that may keep you stuck in Windows.
There are solutions for that as well - Dual boot and VM Machines are available to still use Windows when needed.