You can install them manually by installing them manually on the plug-ins page
- gl-sdk4-ui-nasview
- shadow-useradd
- samba4-server
- samba4-utils
- kmod-usb-storage-uas
or via SSH
opkg update
opkg install gl-sdk4-webdav gl-sdk4-nas-exfat gl-sdk4-nas-utils gl-sdk4-nas-web gl-sdk4-ui-nasview samba4-server samba4-libs samba4-utils minidlna blkid kmod-fs-ext4 kmod-fs-ntfs kmod-fs-vfat kmod-fs-exfat kmod-usb-storage-uas ntfs-3g ntfs-3g-utils dosfstools e2fsprogs shadow-common shadow-useradd