Plumbing - kitchen tap leaking/connect copper pipe to hose

Hi All - kitchen tap is dropping a lot. So we bought a house where previous owner or his/her plumber had got kitchen tap fitted directly by copper pipes running into the tap in-spite of the pipes having an isolation valves. After researching and lot of YouTube and reading I figured the only way out is for me to stop water using isolation valve and then cut down the pipes and then put new kitchen tap. What I am unable to get through to my mind is - the copper pipes already have isolation valves, so there is no point in installing another isolation valves but then how do I connect flexible hose pipe that comes with the tap directly with the copper pipe? It might be a straight forward answer but most of videos only show how to connect using isolation valves etc. any help would be highly appreciated.