Mount the snap fit mounting brackets as above using a zip tie through the top light mounting before snapping the lights into place. You can use a squidge of black silicone sealant as well as the zip tie to to prevent the lights moving once it cures.
Please be carefull here as the lights are a very tight fit and you don't want to damage the waterproof outer sheath on the light. I recommend using some lube like acf50 or wd40 on both surfaces or wrap black electrical tape round the light to protect the sheath where it clips into the bracket. Don't worry if you do burst the sheath it's not the end of the world and can be fixed. Try to have the bottom of the bottom mounting bracket in line with the bottom of the pannier rail as per the picture or when you get to the exhaust side you won't have room to mount due to the exhaust shield.
Exhaust side - same procedure here . Please note that the lights are clipped in nearer the back of the light. This helps to hide the cables when you route them up the pannier rail .
Route the cables up the inside of the pannier frame as above and use a black zip tie or electrical tape every 3 inches or so to keep them tidy then drop them back down and route them between the plastics as per the picture,
Leave a small bight to allow water to drip off the cables.
Job done, stand back, admire your handy work and think to yourself "I am a mechanical and electrical genius and I deserve this cool beer" !!
Hope this is of some help . Regards, Jok