Hi I am total newbie, so far I have been able to add my samsung phone but not my windows 11 pc or Laptop.. what am I doing wrong? do I need to add them in the main app first on my phone or? Help… lol 
Add? In what sense?
It sounds like you’re confused as to what a NAS is?
Ugreen has a pretty good desktop app if you want to use that, but it doesn’t add anything, it simply allows you to access the NAS UI, just like the mobile app.
Normally you set up a network share on the NAS and then go to File Explorer on your PC and either Add a Network Location or Map a Network Drive depending on how you want to access the drives in your NAS.
You need to enable Network Discovery in Windows and rather infuriating on Ugreen NASes, the wsdd2 service, which you find in the Control Panel on the NAS UI, then File Service and Advanced Settings. The latter tends to be enabled by default on other NAS brands.
Then you can also browse the Network in File explorer to find your NAS and the shares you’ve set up.
Other things are in general accessed via a web browser that you point to the IP address of your NAS and then the specific port that program/server is accessed via, unless you install a reverse proxy, but that’s a lot more complex, even if it’s a nicer solution in the long term.