With my L-465 .. once you are in the seat the ECU goes through a self check of all the lights and goes out . Then I attach the seat belt and then turn the key on to allow for preheat and once that countdown is complete can you start the engine. Should I forget to engage the seat belt I have to get my ass off the seat to start the whole process again and do it in that order.
Occasionally blow compressed air thru the seat belt assembly to clean out the crud.
Like other commenters... check all the fuses in the engine compartment and in the access panel to the operators upper right side for continuity and corrosion.
PM me with your email address if you need the operator's manual or the service manual and Messicks is my go-to for parts and diagrams.
Also, put on your wish list of things to do..... take the right side engine compartment panel off and cut off the top 1/3 horizontally. Then weld tabs on the bottom portion of the panel to engage the top portion that you just cut off. Why you might ask? Should you ever have the misfortune of having a starter motor decide to no longer function and your bucket is on the ground, it turns a 30 minute R&R into a several hour exercise because with the boom down, you cannot remove the side panels without the above modification. The manual says that you can R&R the starter motor from inside with the elevated seat , but only in your dreams IMHO.
Enjoy you new toy.....