(Wordpress Beginner) : Transfering(migrating) only the subdomain from the hosting to the another new hosting.

I would like to transfer (migrate) only the subdomain from one new hosting (such as Fastcomet or Chemicloud) from Bluehost hosting.

I would like to know if my steps to migrate the subdomain are right and what I should do do change DNS things…..

** My situation 1 :**
– The main Web domain ( for example : forcleanworld.com) remains on Bluehost hosting.
– Only the subdomain ( for example : blog.forcleanworld.com) should be transferred from Bluehost hosting to the another hosting.

My situation 2:
-The domain registrar of the domain (for example : forcleanworld.com) is Porkbun.
– And the web is wordpress

My Steps :
So far, What I have done is that I have downloaded the files of the subdomain such as DB through phpMyadmin and wp-Contents.
What I should do next is…..

– I should create one web with the name sub.forcleanworld.com on the new hosting.
– And I know so far that I should transfer these files (DB and wp-contents) to the new hosting (I am considering Fastcomet or Chemicloud).
– And then, I should change wp.config.php file in new hosting such as….

/** MySQL hostname */
define(‘DB_HOST’, ‘localhost’);

/** Database Charset to use in creating database tables. */
define(‘DB_CHARSET’, ‘utf8’);

/** The Database Collate type. Don’t change this if in doubt.
*/ define(‘DB_COLLATE’, ”);

Question 1 :
– What I should do next?
I have been informed that I should change DNS thing.

Where should I change DNS? Bluehost or Porkbun or the new hosting( Fastcomet or Chemicloud) ?

** Question 2 :**
– When I should change DNS on Bluehost, should I add ‘A’ Record and refers to other host and fill out the form Host name? And should I fill out the blank ‘points to’ of the IP of the new hosting?

– Or should I edit ‘type A, Shop <- subdomain area’ ?
When I click Edit, the image is like first one and second one below.

When I clock add Record, the image is like below.

Question 3 :
What should I fill out the form to add DNS record or edit DNS Record?

Question 4 :
– What should I do, if I would like to transfer the main domain (forcleanworld.com) from Bluehost hosting to the new hosting where the subdomain exist after transferring(migrating). ?

Question 5 :
– What else such as DNS or something else for setting on the new hosting should I do for the sub domain (shop.forcleanworld.com) and the main domain(forcleanworld.com)?