BY as in "close by"
BY as in "through"
If the English concept was, "We are doing to do this by buying five houses
a year."
You could indicate the concept of "by" by using a rhetorical question:
"WE ACHIEVE HOW? BUY 5 HOUSE every-YEAR"
American Sign Language University ™ ASL resources by Lifeprint.com © Dr. William Vicars