There is not an easy way to copy the content of one site to another.
Content (other than uploaded images or files) is stored in the database not in the file system.
If you are talking about making new unrelated sites then I would use new hosting and a root level site not a sub folder in the current site hosting.
It is also possible to host multiple sites in a single installation of mojoPortal, but myself I would use a separate installation for each of my customers rather than mingle data from different clients in the same database.