Use a mirror to see what you are doing,( borrow a make up mirror from the missus or cut one from an old sun visor) granted there is not much room, less on the battery side.

on the battery side loosen your battery terminals NO NEED TO REMOVE THE BATTERY just undo the securing clamp and shift it over to the left a little. see arrow, use the mirror again, or get a dentist type one like mine in this pic. DONT FORGET TO SECURE ALL THE BATTERY FIXINGS ONCE FITTED.

Then you will have eggless lamps. I have some Osram autobulbs in mine that were donated to me.

This has to be less time consuming than taking the bumper off to remove the lights just to fit bulbs.
Hope this saves you some time.