The worst thing you can do when the light comes on is panic and switch the engine off. A s said above, hold it at higher revs for a good long drive to clear the DPF out. Usually a good motorway drive in 3rd gear at around 3000rpm is good enough. Other thing you can do is get a bypass for it, have it mapped out, then it'll go better. If it is too late and the dash has lit up like Blackpool, then hopefully it won't be too expensive to fix and if it is knackered, get the bypass instead of a new one, will be cheaper.
Black Magic Mk1 Cupra TDI. Got: Green Cotton Panel Filter, Uprated brakes and clutch, Sprayed Wheels, Fabia Wiper, Aero Fronts, CTR ariel, Osram Nightbreakers, Philips BlueVision, Silvertec Indicators tinted repeaters. Need: Milltek Exhaust, Remap, Tinted Windows.