First step: you have to install nodejs and npm , you can follow 6 step for npm bower install on win10 for the installation.
Second step: Create a folder under the npm path (ex. c:/user/kitymindereditor), then, put all files of kityminder-editor download from GitHub.
Third step: launch Node.js command prompt, then enter into the path c:/user/kitymindereditor by the command > cd c:/user/kitymindereditor. Under the path, you will initial the npm by this command > npm run init
Last, you can develop from the index.html under the path (c:/user/kitymindereditor) . Enjoy it.
Note: Image from internet.