Meaning: One and the other; relating to or being two in conjunction.
Pronunciation (sign description): Dominant upright "V" -> "U" (handshape), palm in (orientation), inside non-dominant, loosely "cup" handshape with palm in (location), drawn down from "V" to "U" through the non-dominant hand (movement).
Grammarwise, if you use the concept "both" in BOTH OF US, then there is a different expression in signing.
First 100 words.
As you feel more comfortable with the first few hundreds of ASL signs, progress further with your vocabulary and learn signing more.