## according to the revelation made known to me ##

"that God a revelation known to me" or "that God reveled to me"

## the hidden truth about which I wrote a little previously ##

"the previously not known truth that I briefly wrote to you about before".

## When you read about this ##

"this" refers to the hidden truths that  Paul is making known to the Ephesians.

## you will be able to understand ##

"you will be able to comprehend" or "you will be able to realize".

## my insight into this hidden truth about Christ ##

"my understanding into this previously not known truth"

## which in other generations was not made known to the human race ##

"which was not made known to people in the past"

## but now which has been revealed ##

"but now it has been shown" or “but now it has been made known”