The monitor inputs are RCA jacks; it looks like the outputs from the interface are 1/4" jacks (if I'm reading that photo correctly, the jacks labeled "Main" "L" and "R" are presumably line-level outputs). I can't tell if the outputs are balanced or unbalanced, but it doesn't matter a lot, since the monitor inputs are unbalanced (RCA jacks can't really be anything else).
The obvious way to connect them would be with two 1/4" TS to RCA cables.
Minor technical aside (which you can probably ignore): if the output from the interface is balanced (i.e. those are TRS jacks), putting an ordinary 1/4" TS plug into the jack has the effect of connecting the cold (ring) output to ground. That's generally what you want to do, though there are a few pieces of equipment in existence that want an unused cold output to be floated. This is, I think, unlikely for this piece of equipment ... but you might take a quick gander at the manual and see if it says anything. If it (a) has balanced outputs and (b) the cold shouldn't be grounded, then the manual would say that in fairly definite terms.
Edit to add:
In my experience, cables typically aren't provided for monitors, but you never know. If they are provided, they're likely to be RCA-RCA cables though, so not quite what you need anyway.