Yun Shield set up /www/sd

the original arduino yun has a mini-sd slot instead of the arduino yun shield by dragino
now i asked myself how can I use additional storage with my shield and there is a little description on their wiki

How to set up /www/sd and /mnt/sd?

To use the /www/sd and /mnt/sd as the same as Arduino Yun, user can prepare a USB flash and create directory /arduino and /arduino/www at the root of USB flash. Then input the USB flash into the Yun Shield and it will automatically create /www/sd and /mnt/sd and link to /arduino and /arduino/www
http://www.geeetech.com/wiki/index.php/YUN_SHIELD#How_to_set_up_.2Fwww.2Fsd_and_.2Fmnt.2Fsd.3F

i don´t really understand it and they don´t write much more about it , I tried to put a USB-stick into the USB Type A slot but if I type df -h in the shell it wont show.
if i type dmesg in the shell

[ 261.500000] usb 1-1: new high-speed USB device number 3 using ehci-platform
[ 261.650000] hub 1-0:1.0: unable to enumerate USB device on port 1
[ 270.450000] usb 1-1: new high-speed USB device number 4 using ehci-platform
[ 270.600000] usb 1-1: New USB device found, idVendor=1f75, idProduct=0817
[ 270.600000] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 270.600000] usb 1-1: Product: USB 2.0
[ 270.600000] usb 1-1: Manufacturer: innostor
[ 272.730000] scsi1 : usb-storage 1-1:1.0
[ 273.730000] scsi 1:0:0:0: Direct-Access IS817 innostor 1.00 PQ: 0 ANSI: 6
[ 273.740000] sd 1:0:0:0: [sda] 61440000 512-byte logical blocks: (31.4 GB/29.2 GiB)
[ 273.740000] sd 1:0:0:0: [sda] Write Protect is off
[ 273.740000] sd 1:0:0:0: [sda] Mode Sense: 23 00 00 00
[ 273.740000] sd 1:0:0:0: [sda] Write cache: disabled, read cache: disabled, doesn't support DPO or FUA
[ 273.750000] sda:

How can i prepare my arduino now to use some kinds of extra storage and let it show in my mnt folder and have a link to it with /arduino/www to let it show me the data in the web browser via uHTTPd? Im new into Arduino developing and Linux too and just learn how to use it so i would be happy about some Answers :slight_smile:
(btw. I use an Arduino Uno with Yun Shield byDragino )
Sorry for my bad language im from germany XD