In OpenBSD, you can mount an NTFS file system by using the ntfs-3g utility. ntfs-3g is a free, open-source, and stable read-write NTFS driver that is compatible with OpenBSD.
To mount an NTFS file system in OpenBSD, you will need to install the ntfs-3g utility first. You can install ntfs-3g using the pkg_add command:
pkg_add -v ntfs-3g
Once ntfs-3g is installed, you can mount an NTFS file system by using the mount command with the -t ntfs-3g option. For example, to mount an NTFS file system that is located on /dev/sd0a, you can use the following command:
mount -t ntfs-3g /dev/sd0a /mnt
This will mount the NTFS file system on /dev/sd0a to the /mnt directory. You can then access the files on the NTFS file system by using the /mnt directory.
Keep in mind that these are just general steps, and your specific configuration may vary depending on your system's setup. Consult the OpenBSD documentation for more detailed information.