sharepoint - powershell create new spweb -

how can create new instance of spweb?

i don't want use get-spweb or new-spweb don't want existing object, or create new page.

i want create spweb object , set it's guid.

i not quite firm powershell , sharepoint, can't create spweb without supplying information. doesn't make sense @ all.

from msdn

new-spweb:

creates new site in existing site collection.

new-spweb [-url] <string> [-addtoquicklaunch <switchparameter>] ... 

where url required parameter.