You'll need to source a switch block or splice something in..
I have an entire spare wiring loom here that I was given from a 2013 that upgraded to an e-start (different loom req to add battery etc).
In short, the yellow AC comes direct from the stator. Under the tank on the frame you'll have the CDI which connects into the loom, a regulator (small black box mounted to frame, and the coil.
Everything else then runs up around the head stem and has plugs for the headlight, blinkers, horn, etc. I can't recall from memory, but I think the flasher unit for the blinkers was also included in the switch block on this model. They aren't a cheap replacement.
This gives you an idea of the loom:
https://www.motocrosscenter.com/shop...50-racing-2013
Ref. EE10000043012 costs 85 Euros...