problem while adding a model into a map

I have a problem while adding a model file into a map
I don't know what i was wrong
First i add a model name
units\demons\infernal\inferna1.mdl
units\demons\infernal\inferna1.blp
I have changed the hex
Then i use UMS WORLD EDITOR
Change the infernal unit model to my new unit model
From
units\demons\infernal\infernal.mdx
to
units\demons\infernal\inferna1mdx
It worked correctly in world editor:foot:
Then i play this map but the infernal didn't appear
And i reopen my map and a error message dispaly in the bottom

cannot open units\demons\infernal\inferna1mdx
What wrong ?

Do not open and save your map in WE since you have inserted your files.
Copy your map under Warcarft maps directory and play using Warcraft directly ;)
Hope this help :)

Did you implement it? you gotta implement it. And dont open it once you implement it, it erases all files from the map that arent there by default.

Thank , the map works correctly now