Cleaning and Maintenance Steps

First Steps:

Remove the fans and extruder motor from the extruder assembly (check for any filament build up that possibly could be the cause around the gears of the motor). Unplug them from the small extruder PCB if possible, remembering which socket they used.
When they are out of the way, heat up the extruder to about 245 degrees (via the preheat menu) and use the hooked wire from your kit to push the filament down via the nozzle.
Hopefully this unblocks the nozzle and moves out any excess build up, being careful not to use too much force so the wire bends, etc.
Re-attach the motor, fans, etc. and then use the Add Filament option to get the filament flowing through the nozzle ready for a test print.

(When test printing, use one of our test Gcodes or a print you know 100% works such as the Test Benchy in the link below these steps)

Secondly If this doesn't resolve the issue, I would try Replacing the PTFE Tube.
Make sure the extruder is cool, and using two shifters, hold the heat block with one and unscrew the brass nozzle with the other.
Remove the brass nozzle and the PTFE tube behind it. (The tube can be replaced with the spare in your kit.)

(Mark sure to let the printer cool down before removing the PFTE tube or use tweezers.)

The nozzle can be cleaned with tweezers once removed.
Once cleaned, insert the new tube and screw the nozzle back into the heat block ready for a test print with a known working Gcode such as the Test Benchy Below.