- Search the web to find which piece of software suits your needs.
- Find a web site that allows you to download it.
- Maybe pay for it.
- Actually download the software.
- Install it.
- Sometimes reboot your computer.
With Linux, everything is much simpler. Linux has what is called a "package manager": each piece of software is contained in its own "package". If you need some new software, just open the package manager, type a few keywords, choose which software you want to install and press "Apply" or "OK". Or you can just browse existing software (that's a lot of choice!) in categories.