Hi Ernest, welcome to the forum.
If you had Sibelius open when you copied/pasted the XML files, you'll need to restart Sibelius so it will load them. If you still don't have them in the drop down list after that, then you've inadvertently placed them in the wrong location. Find those files and double check the directory path. Are they in the "Sounds" folder? (There is one other place where Sibelius will see them, but Sibelius central recommends only placing sound sets into the users folder.)
The sib file and PlayTest folder don't have any specific place where they need to go/be.
New or not, please be sure to thoroughly read the Readme file. And if you still have questions or problems getting things setup, you know where to find me.
Hugh
If you had Sibelius open when you copied/pasted the XML files, you'll need to restart Sibelius so it will load them. If you still don't have them in the drop down list after that, then you've inadvertently placed them in the wrong location. Find those files and double check the directory path. Are they in the "Sounds" folder? (There is one other place where Sibelius will see them, but Sibelius central recommends only placing sound sets into the users folder.)
The sib file and PlayTest folder don't have any specific place where they need to go/be.
New or not, please be sure to thoroughly read the Readme file. And if you still have questions or problems getting things setup, you know where to find me.
Hugh