Let's dive into bootstrap and get your first site up.
NOTE: If you are a PC user when you zip/extract the Bootstrap zip file it will take you to a folder titled bootstrap-3.1.1-dist or with a number similar to that - 3.1.1 is the Bootstrap version number. Take that file and rename it first-site. Then copy the file and paste it on your desktop. Once you've done that open the first-site folder in Sublime as directed in the next step.
On a mac you can grab the first-site folder and drag it over Sublime app icon (if the Sublime app icon is in your bottom app doc) to open. Otherwise open Sublime and click File at the top, then Open Folder or Open if on Mac. Locate the first-site folder, highlight it and then click open.
Right click on the "first-site" folder and choose new file. Highlight the code below (or on Bootstrap site) and insert it into the document. Save the file and name it "index.html".
Find your file (in finder for mac, in your folders for pc) and right click on it selecting "open with" > "Google Chrome". Nerdy tidbit: Hello World is common practice among coders to do as their first program or output in any new coding language. Welcome to our world!