There are only two programs you need to start Storyboard.
Cytoid Player and a text writer.
You can get Cytoid Player here.
It's very recommended that you use any text program that supports syntax highlighting, considering you will write a text that is sensitive to double quotes, commas, brackets. The notepad that start with windows won't give you those features.
Notepad++ is recommended for it's highlighting and also auto spacing for better code reading. If you don't like Notepad++ you can use whatever you want.
But, if you want something robust, powerful, and supports crazy amount of highlighting that makes checking mistakes like a breeze then I recommend you to use Visual Studio. It's free. Just download the community version. It also supports auto spacing, and automatically add close brackets and double quotes whenever you want to write one, so you will less likely to have mistakes on the number of brackets that needs to close the open ones.
Visual Studio however, takes a lot of space and has huge size to download, and if you only storyboard simple stuffs... it's best to stick to something simpler like Notepad++.
As for the rest, just read the guide located on Storyboard
Example of Storyboard. Daunting? Most likely, but it's harder than it looks. It's fun after you learn how to do it.