This should probably go in the discussion and analysis of data section.
I'll obviously link to the two artefacts (maybe from representatives image rather than just a text hyperlink) but alongside that I will need to offer a bit of background to the two artefacts, including in which ways they might be viewed a multimodal, how they differ, why I chose them, some very brief detail on the nature of the stipulated assessment exercise, the course they were a part of, what the assessment criteria was for the exercise.
Rather than being at the start of the section, this would be part way through. Amongst other things it would be a nice way of breaking up that section (which will be text heavy). Also, it wouldn't sit well directly after the detail outlining the nature of the DE course that will at the beginning of this section.
Is it worth taking the thinglink approach here, using the literature to highlight the different modes. Perhaps I would take a screen shot of each assignment with the overlaying information (thereby allowing for sound, through the volume icon).