If two operands are required then separate them with a comma and whatever space delimeter you want. These can be entered in a source code file that you create with the editor, but they cannot be directly entered with the debugger. Do not use comments. Usually you are told to put comments in your code. However you do not enter comments in the debugger.
All numeric constants are always in hex.
The operand value is in a register. You shouldn't mix words and bytes. You can't move directly from one segment register to another. The operand value is referred to in one of two ways. Remember that there are 3 steps to saving a file in debug.