You add nodes from CherryTree's Tree Menu. Once you've created a node, one of the things you can do is associate that note with a datafile you've already created using a different application. For example rather than Edit>Insert Table --which will create a rather primitive table structure-- you can either Edit>Insert
File or Edit>Insert/Edit Link to a Word-process Table or Spreadsheet. Either way, double-clicking the node opens the datafile in your operating systems default application for that type of file.
I think Edit>Insert Link works better. The data file 'seems' to open faster and mfb reported CherryTree closes more responsively. If I'm not mistaken, Insert >file actually embeds the document into the CherryTree File and may be necessary if you're going to save CherryTree files to a USB-Key for use on more than one computer. But, I may be wrong.
CherryTree appears to use mine-types to associate datafiles with the applications to manipulate them. At least, I think 'mime-type' is the technical term for a file's ending which reflects how it was formatted; e.g. .odt is the file-type, 'open-document-text', which is the default formatting used by both Liber-and-Open Office Writer and available as an option under Textmaker.
Planner is an application available via PPM in many Puppies. See Screenshot. It's file-ending is ".planner". CherryTree opened it as a text file. Not very helpful.
However, I could customize Rox's Right-Click Menu to "Set Run Action" to open *.planner files in Planner. With that association set (Restart-x may be required) CherryTree opened a node of a *.planner datafile in Planner.
(Remember to Save such settings to your SaveFile/Folder).