How do I use the conversiontypes?

I am creating an image with swupdate and am trying to use the conversiontypes in order to create the zck and zckheader files for my delta updates. The swupdate layer has a bbclass for adding those types and conversion_cmds for both. see here: https://github.com/sbabic/meta-swupdate/blob/kirkstone/classes/image_types_zchunk.bbclass The issue is that I can;t seem to figure out how to actually use the bbclass, I've tried multiple different things and have tried to look up documentation on this. The only thing I could find was the implementation of the types and the command in which to generate the image, which is done in the layer, but no instructions on how to get bitbake to actually build the conversion output files.