You don't give any details. Are you trying to just transfer the web files only or trying to move a domain to your account. If moving a domain is this a full transfer including ISPTAG change or just hosting only?
If just websites you use FTP to transfer them to your webspace.
If a domain, its not a good idea to transfer your domain to plusnet. If the current domain host does nt support hosting on another ISP, move the domain to a registration company (like 1and1 or 123reg) then arrange to host the domain on your account by following the help & support instructions on transfering domain hosting to plusnet.