Getting ready to do migration newbie questions :)

Hello, I am a newbie at all this and have some very basic questions ??

I am planning on doing a migration from a subdomain to a domain with your plugin, both are on the same server and in the same Cpanel…I wrote to you a week ago.

I have changed the DNS for the domain name and now waiting for the propagation to complete.
I’ve added the domain name in my Cpanel and I was told by my host that I can set up a new wordpress install for this new domain name right away while I wait for the propagation. Could you confirm that this is a good idea?

When this propagation is complete: not quite sure how I’m to know ??

1) do I upload anything at all to this fresh wordpress instll before doing the migration? such as the theme I am using?

2) I’ve checked in the wp-content file and the permissions are all 0755 except for the .index php which is 0640…do I leave it as is or change it to 0755 as well?

3) Can I set up the new WP install with the same admin username and password…just to keep things simple? ??

4) When I export out of the subdomain WP install, is that wp install cleaned out of all info or is it left as is?

5) from the short video that makes a website migration all seem so, so simple ?? I don’t need to do anything other than press the export button…the plugin will make all the file extension changes all on its own. I just want to make sure since many years ago a host migrated a website for me and it took many days to clean it up

Please forgive such basic questions, I really want to do my best to make sure this migration is smooth.

Thank you in advance for your attention.

https://www.ads-software.com/plugins/all-in-one-wp-migration/