Is always so much easier to understand with a picture!
I think that eQuilter link is a good place to start. Basically what you want to do is to incorporate your pieces into a larger project and there are different ways to do that. One way is create a center and then use different border options.
Some math/changes may be needed to fit your exact panels.
Here's a project with very different fabric but made from rectangle/square panels:
https://www.equilter.com/pattern/1107/lovable-labradors
or here's another design based on squares and rectangles
https://www.equilter.com/pattern/1053/wildlife-wonders