Help please

Higgy1974

So guys n gals, the pipe on the left has been attached to my dishwasher since Before I moved in, I’m changing dishwashers and it’s not coming until tomorrow, I know I need a bunch to block it up until then, my question is...when I fit the new one tomorrow do I need something to stop water and any waste going from the sink back into my dishwasher? 

Thanks in advance and yes I know the plugs are in a crazy place but I didn’t put them there lol 

grumbler

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