To install Atom packages, you can navigate to Atom > Preferences > Install,
search for the package name, and click Install
To change the settings for these packages, find the package in Atom >
Preferences > Packages and click the "Settings" button.
Make sure none of the "On Save" settings are selected

Change the "Keymap for Confirming a Suggestion" to "enter" so that it doesn't conflict with emmet.

Ignore some files so that things like .DS_Store don't show up in your sidebar.
