To install xboard just follow these instructions.
sudo apt-get install xboard
Which will install xboard and any other packages on which it depends.
|Maintainer||Debian Games Team <firstname.lastname@example.org>|
|Description||X Window System Chess Board for chess programs, for the Internet Chess Server, or for electronic mail correspondence chess. It supports all major forms of chess, such as international chess, xiangqi and shogi. XBoard can also be used by itself as viewer for stored chess games.|