I had warranty direct cover for a few years and had the need to make two claims one for a CV joint on the front driveshaft and a second separate claim for a replacement gearbox, both the claims were handled in a very straight forward and uncomplicated manner.
It is conditional that the car is serviced at the correct intervals in accordance with the manufacturers service schedule, give or take 1000 miles (it used to be, so check). They will ask what the problem is and the quotation costs and need to see copies of the applicable service records when you phone for a claim authorisation number..... you need this authorisation before giving any garage the go-ahead to carry out any actual repair work.
Words of caution though, as with any insurance based product always thoroughly read and digest the small print to see if the policy is correct for your needs rather than making assumptions, make absolutely sure that there are no misunderstandings regarding your consideration of what is.. and what is not covered, before you commit to buying.