The bodies snap into the portals. I found them to be very tight, but they will snap in.

If you use the STL's, note that the snap fit arms are about 1 layer thinner on one side to fit in the holes better. Make sure you print with the correct side facedown.

I included my BambuSlicer 3mf files for multi color printing, but a single color for the portals should also look great.

For the magnets, I use 30mil magnet sheets which I find are strong enough for most uses and just glue them on the back. I included a PDF you can print as a template for your magnet. I find that having a magnet that's smaller than the model makes it easier to grip and move. Totally optional.