I want to add avery 5230
Do you mean: "I want to add my own label definition of Avery 5230, so it appears in dialog File -> New -> Labels"?
It is probably easier to add in your own dimensions for the labels than to convert one made for Word. Have a look at question 305268 to see a template dialog to create Avery 22828. It is easy, just remember to save it with a suitable name so you can use it again in future.