Welcome Dobie Lover. Pet Talk is a fine place and the members are really helpful and nice people.
Its a long time since I had my Dobies but I recall that they were both very bright dogs and caught on very quick to what was required of them. Having said that "a firm hand" so to speak is what is required, NOT in a physical way but rather a firmness and most of all a continuity in everything. No letting them get away with something one day, for example, letting them jump up, then stopping them the next day. Same as in training all dogs I suppose, except that maybe Dobies are a little quicker in taking advantage and trying to gain the upper hand.
But, like I already said, its a long time since one owned me and I`m sure there are others, (maybe especially bnormal who is actually owned by two beautiful ones right this moment!), who are much better placed to tell you what you want to know

When you say "chat" do you mean sending a private message to one of the Pet Talk members? If so, and you haven`t figured it out yet, this is what you do. Click on the profile of the person you want to message and (if the person has enabled it) you will find a part that reads - Send (whatever the members name is) a private message - just click on that and go from there. Hope this helps