The simplest answer is to put it back the way it was.....if that works - then it must be something you've done....then it will be a process of elimination.

Pop the fuel hose of the carby, pull the IGN lead of the coil - crank the motor - see if fuel comes out of the hose (into a jar you hold over that hose).

If that works then you should be good - if it doesn't if either fuel filter wrong way round? or fuel pump in trouble.

It's all in the workshop manual (the fuel system diagnosis) by the way.