Awk Sed question

i have to search direcotry with a Min or Max size and but with a standard find.... it gives me the size of the i-node of the directory.
A friend told me to use awk/sed command to search directories.

he also gave me this command:

find [path] -type d [other options] -exec du [with or without -s] '{}' \; | awk -v sz=10 '{if ($1<sz)print}' | sed -e 's/^[0-9]*\t//g $minVar

someone can tell me if this is correct, what each command means because i don't understand properly these commands, and if is it correct how i can modify it to use a range of size (something like -size +2B -size -50M).

Tnx for the help.