Permalinks on Frame-Forwarded Domain

Hi,

My blog domain is https://www.myhosteddomain.com/myblogdomaindirectory/
I don’t want ANYthing referring to the host domain, anywhere.

My understanding is that if I choose CUSTOM STRUCTURE in PERMALINK COMMON SETTINGS, I can enter the following text:

https://www.myblogdomain.com/%category%/%postname%/

and all permalinks will appear as

https://www.myblogdomain.com/categoryname/postname

Is that correct, or do I have to something else? I ask now because when I tried to alter the blog url settings to eliminate the hosted domain name, the whole blog–along with the dashboard–vanished.

Thanks for any help!