Can I use a sprinkler with this pump?
Yes, you can.
How do I connect this to a normal hose pipe for watering the garden?
Please refer to the instruction manual for this pump, where it will show you how to do this. You can find the instructions online: https://www.hozelock.com/product/hozelock-jet-3000-k7.
Can this pump be used in a water butt?
No, this pump is not designed to be submerged in water, but it can be used externally using the suction pipe inside the water butt to draw the water out. If a water butt pump is preferred, take a look at the Flowmax Collect 2200: https://www.hozelock.com/product/flowmax-collect-2200.
Will a standard size hose fit the supplied fitting?
A standard hose is 13mm, but the jet pump will only fit 15mm, 19mm, 25mm or 32mm hoses. This is due to the high output of the pump.