Chosen Solution

How do I replace the left rear tail light assembly on my 2013 Toyota Avalon Hybred

There should be some screws inside the trunk which hold the tail light assembly on.  You’ll need a Torx bit to loosen / tighten the screws - I don’t know which size - go to an Auto parts store - they will let you try out different sizes till you find the correct one.  Once you find the screws, it will be easy to remove / replace.