The ttf files need to be added to the Resources section of your project. Then the names you put in the Info.plist file (your Marsden-Info.plist) needs to match the filenames of the ttf files.
You entered Lexia-Regular.ttf
and Lexia-Bold.ttf
but the files appear to be named LEXIA___.ttf
and LEXIB___.ttf
. The names must match exactly, including case.