Great review after 5 hours of using Meteor? You couldn’t work out how to add SASS or even add packages, but already have an opinion…
Meteor is definitely at an interesting crossroads right now, but this post was close to pointless.
Here’s the Sass package you want: https://atmospherejs.com/fourseven/scss
And add it with: meteor add fourseven:scss.
Blaze is actually beautiful btw. I wouldn’t recommend developing Meteor apps with it nowadays however unless you have a legacy app. React would be the way to go. (Or Angular 2).