Fuel, ignition, and Compression at the right time. All they did was change out the clutch? It ran up until then? Now they want to throw it in your lap and say take off... They need to find someone smart enough to fix it. Someone smarter than the engine. I'm finding this hard to do at my local dealers.
Throwing a little gas in the intake is a trick I do sometimes to prime the engine. It will also tell you you have a fuel system problem when the engine fires for a few seconds. Just be real careful with the gas. Don't leave the gas can near the car because it may back pop and set it on fire. Close up the intake because the air filter will stop the flame if it back pops.