More context needed.
1 - When it did it last successfully start and run?
2 - What has changed since then?
For a reliable engine like the EA113 to not fire up at all, something drastic has happened.
As the other esteemed gentlemen have suggested, it's a back to basics approach.
Fuel, air, spark, compression and timing.
All of those need thoroughly checking, not to mention wiring harness integrity to make sure the ECU is actually getting a strong signal from the crank sensor.