Can't get multiple templates to work - Joomla! Forum - community, help and support

hi

i want have 2 template website joomla 3.6.5:

the main 1 pages there, and....

a new template single menu item.

here's i've done it's not working

1. uploaded new template
2. created new menu item , set template style new template
3. went main template , unchecked new menu item
4. went new template , checked new menu item

however, when view menu item...it still shows old template.

what step have missed?

thanks
pam

did clear server cache?