Thanks for posting. You can create links to pages you create in your document, links to web URLs, as well as links to other documents. When you create a new document in VoodooPad, it is saved as a .vpdoc file. You can back up each .vpdoc file to an external hard drive and open it on your new computer when you have installed VoodooPad there.
If you plan on creating links to other documents (e.g. Numbers documents, Pages documents, etc.) within your VoodooPad document, I recommend doing this by going to File > Import and importing them directly into the document. This way, the external document will be within the .vpdoc file when you move it to your external hard drive, and you will not need to relink it. The external document will be saved in your pages list.
If you would like, you can download a Tryout version (with some limitations) before you purchase a license. You can do this here by clicking "download": https://www.voodoopad.com
Let me know if you have any other questions and I'll be glad to help out.