Help? Move shop to sub-domain

My shop currently resides on http://mydomain/shop
I need to move it to subdomain: http://shop.mydomain

How do I configure such things as:

DIR_WS_CATALOG -- currently is /shop/

etc.?

I just tried and broke my template entirely :(

Easiest:
Create your sub-domain and install ZenCart fresh there
This will generate the correct configure.php files

Edit these 2 files and change the DB info to your current /shop DB details and Save these

Delete the install you just created

Move or better yet copy all of your current shop files to the sub-domain location
Replace the 2 configure files with those that you saved

The shop at the sub domain should be good to go

well but the way my server is configured, the new subdomain shop.mydomain.com is set up to point to mydomain/shop

So technically, it all works fine at present.

The real issue, however, is that mydomain.com is now going to be hosted elsewhere -- though the shop will remain on my server SUBDOMAIN with an A Record set up.

I'm told that I need to change config so that all works from subdomain rather than primary domain.

I thought it would be easier to just manually edit the config files -- but am unclear as to how to do it correctly.

Adding a new post because it is several days later and I could use a little help please :lookaroun

I've purchased a self-signed ssl cert and changed admin and main config to point to the subdomain shop.mysite.com

All works fine EXCEPT for one spot that I simply cannot seem to find to fix.

In the header menu it shows SIGN IN | Shipping Info | Contact Us .... and that SIGN IN link is still pointing to the primary domain NOT to the subdomain. All other links are correct, including the Would you like to log yourself in ... etc.

Link is here if anyone can advise on how to change this one little glitch? THANKS :)

SOLVED -- internal link URL had been set on EZ-pages for the sign in page for some reason. All better now :)