devices with the same user name and password should be able to access shares without being asked for a password. You may be able to access shares on your other devices with you login/password or even save the credentials to it.
The properties on a shared folder have a security and share tab that can be used to set permissions. You have to make sure the security permissions are at least as restrictive as the share permissions because they will over-ride share permissions for allowing access(share has access and ntfs security has no access than no access will win).
It does not take long to set permissions and gets things fixed up.