If that is the only cold feed pipe it also looks like it has something already connected, maybe your washing machine?
You could use a Y connector i would advise getting a brass one not the plastic version.
Waste water will need to go out via your U bend if you do not have a stand alone waste pipe that goes directly outside, by looking at your photo then you are correct in assuming thats where the hose connects, unscrew that cap and you should have a spigot that attaches where the cap goes, dont forget to cut the blanked off end of the spigot otherwise the water will not flow through and you will get faults on the dishwasher.
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