You want to be able to go through a scenario step by step when you are testing with a browser as sometimes can be very fast.
By following the suggestion here you would only need to add the following to your features/support/hooks.rb file
AfterStep('@pause') do print "Press Return to continue ..." STDIN.getc end
and then you should be able to use it in your scenario by adding the @pause tag.
Then you would have to press continue in your terminal to go step by step