How to attach a bottle with water to a water cooler without spilling the water?

I plan to buy a water cooler to use at home. And to buy the water in bulk with my own bottles, because it is cheaper (I already buy the water that way, but I cool it in the fridge).

And here comes the problem: how can I attach the water bottle to the cooler without spilling the water?

The special 4 gal / 19 l water bottles come with a special (simplistic) valve, but my bottles will no longer provide such luxury, unfortunately.

Buy one water bottle with a valve that is specifically for the cooler.

Then refill that bottle from your cheaper source. This avoids trying to find a way to fit your cheaper bottles to the cooler.