## went up ##
or "traveled." Jerusalem is located in hilly country. The Jews also viewed Jerusalem as the place on earth that is closest to heaven, so Paul may have been speaking figuratively.
## I should go ##
"go to Jerusalem." or "go there"
## those of repute who were leading the others ##
"the most important leaders of the believers" (UDB)
## for nothing ##
"for no benefit" or "working uselessly" (UDB)