A good game provides the player with some information on how to play the game. This information is displayed when the player presses the <F1> key during gameplay. To create the game information, double click Game Information in the resource tree at the left of the screen. A little built-in editor is opened where you can edit the game information. You can use different fonts, different colors, and styles. You can also set the background color.
In the File menu, you can set a number of Options. By default, the help is shown in the game window and gameplay is temporarily halted. You can indicate to show the help file in a separate window. In this case, you can indicate the caption of the game information in the game. You can also indicate the position (use -1 for centered) and size of the game information window and whether it should have a border and be sizable by the player. You can force the game information window to stay on-top and you can indicate whether the game should continue playing while the game information is shown.
A good piece of advice is to make the information short and precise. Moreover, don't forget to add your name as part of a "Credits" section. All example games provided have an information file, typically called a Readme, about the game and how it was created. You might want to indicate at the bottom of the help file that the user must press Escape to continue playing.
If you want to make a bit more fancy help, you can use a Word Processor like LibreOffice Writer or MS Word, or branch out and use HTML. For more advanced games, though, you probably shouldn't use this mechanism at all, but instead use some dedicated rooms to show help about the game.