Welcome to LQ!
For start create /home/you/bin directory, then add/copy "doc2unix" executable to it.
Then add /home/you/bin to the PATH by editing .bashrc file in your /home directory and adding export PATH=$PATH:/home/you/bin:
line to it.
That's for start. Search, learn. For start go here
All of this if "doc2unix" is not already there. I don't use Slax.
to see if it's in the PATH.
to see directories being used for executables.