Console and live usage
Issuing commands, reading the output, and what the bars mean.
The console
The console is your server's real standard output, live over a WebSocket. What you type goes in as standard input, which is exactly where it would go on a machine of your own.
On a game server that means every server command works: op, whitelist, say, stop.
The bars
RAM and CPU show what the container is actually using, measured by the machine rather than estimated. The limit beside it is your plan's.
Green is normal, amber from around four fifths, red just below the limit. Red on RAM is worth looking at: a Java process that runs into its memory limit does not get slow, it gets terminated.