Hi, Jessica-
The Windows Subsystem Linux (WSL) is *not* replacing your Windows OS: it is an application that is run *within* Windows, a program/application that you open, use and can close (e.g,. like a browser or Word, etc.). But this is not a virtual machine, either---it has better performance. You can send files back and forth from the Windows filesystem to the Linux section. You can use a browser natively from your Linux part.
This WSL is different than partitioning your harddrive and adding Linux as a separate OS or overwriting your Windows (neither of which I am recommending here).
--pt
