When I click Edit Script, the program closes.

Open the map, go to Map Properties Tree => MapScript => Click on the line => New => Enter a name, for example, MainScript => OK. Save and close the map. Then, download this pack -> https://yadi.sk/d/W6cz5UBu3SGAvb, open the practice folder => ... run the H5MapScriptsEditor program located there. File => Open => Go to the Maps folder and select the map. When the map opens, open (if it's not already open) Maps/SingleMissions/MapName in the file tree on the left. Click on any file displayed in this folder. Then, click File => New *.lua => Enter the name MainScript.lua and click OK.

Save and close the script editor. Open the map editor and your map again, go to Map Properties Tree => MapScript => Click on the line => 3 dots => In the properties window that appears, find the first property line on the top right and enter the path to the script file: /Maps/SingleMissions/MapName/MainScript.lua. If the line does not disappear after pressing Enter, then you have done everything correctly. Save, close the editor. Open the script editor, your map, double-click on the MainScript.lua file to open it, and then enter your script.