You attempt to return the Vulcan’s gesture… but end up just sticking your hand out for him to shake.
The Vulcan says “live long and prosper.”
“Thanks” you reply.
“We welcome contact with your species” continues the Vulcan. “We are explorers who seek peace and knowledge. We know that your species has now achieved warp flight, a most important step for any young race. Perhaps one day we could be of some use as guides as your species takes its first steps out into the galaxy?”