Right way to add folders in arbitrary locations to sync?

I want to make sure that I’m doing things right - to prevent data loss…

I want to sync the following two folders across devices:

PC 1 (to be created)

Mac 1 (existing)

In the app on Mac 1 I should
Add folder sync connection
Pick the local folder

Set the remote (server) folder
/Nextcloud/my_data (should I put is somwhere else - what makes sense?)

Then on PC 1 I need to do add the sync connection and point it to

  1. Do I have to wait until sync up to server is finished on Mac 1 (otherwise it will try to delete all the files on the

  2. Also - if I am using my own directory structure that is heterogenous on the Mac 1 and PC 1 clients - should I turn off the sync of the default /NextCloud folder (otherwise I end jup with two copies on the clients, one under /Nextfcloud/my_data and the other under /usr/me/Documents/my_data - right?

I have tried reading the docs - but I want to make sure that I have understood things for my use case before terrible things happen…