Ever since the beta, I have had trouble making a unit. And I haven't played or touched starcraft 2 in almost a year now. So now I am trying to create a new unit, I have been having lot of trouble finding a tutorial . This kind of thing used to be extremely simply in wc3. Now? Not so simple. Granted, if you know how to correctly its not hard.

Could someone tell me in good detail how to create a unit? (Or a really good in dept tutorial link) Just for a mere example, something as simple as copying a marine fully.

Would greatly appreciate it

Try this: http://www.galaxywiki.net/Creating_a_unit_from_scratch

Or alternatively, copy a unit by selecting it, right clicking, and clicking Duplicate. Then select only the actors in the box that pops up.