# my masters
This was a term of respect Lot used for the angels.
# please turn aside into your servant's house
"Please come and stay in your servant's house"
# wash your feet
People liked to wash their feet after traveling.
# we will spend the night
When the two angels said this, they were referring only to themselves, not to Lot. The two of them planned to spend the night in the square. Some languages would use the exclusive form of "we" here.
# town square
This is a public, outdoor place in the town.