You need to put the following or similar lines in your .tcshrc, .cshrc,
or similar file depending on what shell you are using. 

setenv TETEXDIR /usr/local/teTeX
setenv PATH $PATH:$TETEXDIR/bin/sparc-sun-solaris2.8
setenv MANPATH $MANPATH:$TETEXDIR/man
setenv INFOPATH $INFOPATH:$TETEXDIR/info