Plugin is not dependent on any other plugin. So it can run alone without any issues. Some limitations can appear, like limited economy usage. But other then this, place plugin file into plugins folder, start server and you are good to go.
On first run plugin will create quite few default files, this includes locale files which can be used to change and translate plugin output messages to your own liking.
CMI will not give access to commands by default. Regular player will not gain access to any command without giving particular permission node for it.
Commands by default are in long format like /cmi heal [playerName] this can be changed in 2 ways: First is to enable predefined short commands in alias.yml which will change it into /heal [playerName] and performing /cmi reload or server restart. Second is to create your own short command with /cmi aliaseditor command, in this example /cmi aliaseditor new heal-cmi heal $1-
In case you are transitioning from Essentials you can utilize /cmi importfrom essentials [home/warp/nick/logoutlocation/money/mail] command to import players information which can include his balance.
By default CMI will use sqlite database, in case you want to change it, you can achieve this in 2 ways: First one is by changing method in config.yml file and reloading plugin. This method will not save current information you might already have. To convert into anything database type without loosing any data use /cmi migratedatabase which will transfer data from sqlite to MySQl or vice verse depending on your current system. This requires you to have MySQL data to be set correctly (password, username, tadabase name and so on)
Economy is disabled by default. You can enable it in config file and you might need to perform full server restart for it to take full effect.