I'm sorry if I'm underestimating you, but it sounds like you don't really know much GUI.
The easiest way to make a custom race is to just use the "base" peon-type unit from the standard race and change it in Object Editor. For example you could use a Fel Orc Peon instead of the model for the standard Peon. Now you have a custom worker. The same goes for the starting Hall. Change the name, model, icon and tooltips and you have a new starting hall. Then you can change the peon's list of buildings that he can build. Again my apology if this is too simple and not useful.
Creating a 5th race is a little trickier but can be done in several ways too. Trigger the starting units with standard Melee Game actions and trigger the custom unit with triggers setting the starting units and resources.
For now my guess is you need to become an Object Editor master and then move on to the more complex work of GUI. I might be wrong, please don't take offense.
You can also make custom spells in Object Editor by changing stats, buffs and effects. GUI spells are a bit more advanced but there are some good beginner spells here in the spells forum. I suggest downloading an Altered Melee map with custom races and looking through every part of the editor to see how someone else created their race. Look at trigger editor, object editor, gameplay constants, player properties, force properties, etc. Look at everything. This should give you a good idea on how to start. Then if you can't seem to get something done, post a specific question here. I hope this helps and again, if you are already past this stage, I'm sorry, please don't take offense. Its hard to tell where someone's skills are sometimes.
Remove the starting units trigger and do this at map initialization...
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Actions
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Unit - create 1 custom_unt for (player 1(red)) at position of (starting location for (player 1(red))
repeat as needed.