As adverbs the difference between next and below
is that
next is in a time, place or sequence closest or following while
below is in a lower place.
As prepositions the difference between next and below
is that
next is on the side of; next to while
below is lower in spatial position than.
As an adjective next
is following in a sequence.
As a determiner next
is the one immediately following the current or most recent one.
As a noun next
is the one that follows after this one.