To create a block, use the bem-tools command
bem create -l whatever.level.this.goes.to -b my-block-name
I have yet to develop a good organizational ontology1 for naming levels, so your guess is as good as mine as to what the best practices are for naming levels.
Blocks seem easier to name, as they are generally some kind of structure. I've been using things like “button" or “title" or “search-bar" or “advanced-search" for names.
Once you've created blocks and have a bundle you want to look at2, what do you do?
You run the bem server! The bem documentation says running
bem server works, but in my case, I need to specify the ip address. I also specify the port, because I run a lot of different things on my workstation. For example:
bem server -p 8080 --host=127.0.0.1
Once you've done that, browse to http://127.0.0.1:8080 and you should see the bem server index page giving you diagrams of your bundles and links to your bundles' index pages