# his sons

Here "his" refers to Aaron

# toward the sunrise

"on the east side, where the sun rises" 

# performing the duties of the sanctuary

"doing all the work connected to the sanctuary" or "taking care of everything connected to the sanctuary". See how you translated similar words in Numbers 1:53.

# Any foreigner who approaches the sanctuary must be put to death

"You must kill any foreigner who approaches the sanctuary" or "Any foreigner who approaches the sanctuary must die"