A burst pipe is stressful, but the first few actions usually decide how bad the damage becomes.
Turn the water off
Shut the stopcock first so no more water is feeding the leak.
Drain what is left in the system
Open cold taps so the remaining water in the pipework can run out rather than continue soaking the area.
Protect the room and call for help
Use buckets and towels to contain the water, take photos if you may need them for insurance, and then call Alan so the leak can be traced and repaired properly.