If I am using Joe as my command squad how do I get the artillery long tom off? Do I have to have line of sight with him even though he does not have a radio? Also, can an observer team be put into a unit, or put in with joe to give commands board wide?

Thanks for the help!

You need to issue the order to a unit that has a Radio. So you would need to have joe attached to a Unit with a radio or Issue the order to a squad that has one.