I have a s55v16a-au and want to know how to use a usb. I have put it in but din't get an option to open it

Let's explore your options:

Double DIN Stereo Upgrade Kits:
There are aftermarket double DIN stereo upgrade kits available specifically for Citroen C3 (2010-2016) and Citroen DS3 (2010-2019) models. These kits include everything you need for a seamless installation, including a fascia kit, plastic brackets, screws, blanking buttons, steering wheel control interface, antenna adapter, USB and AUX retention leads, and a universal patch lead.

The installation process involves removing the original single DIN radio, fitting the new plastic frame and fascia around the double DIN radio, and connecting the wiring harness and other components. These kits are designed to retain steering wheel audio controls and other features.

Keep in mind that dashboard modifications are required, so professional installation is recommended.

Connects2 Adapters:
If you choose an aftermarket stereo that isn't specifically designed for your Citroen C3, you can use a Connects2-style adapter to convert a compatible aftermarket stereo to control the screen above the radio (date/time, etc.) 3. This way, you can still access essential information.
For example, a Double DIN Android Auto-compatible stereo like the JVC KW-M560BT could fit in the space after removing the cubby and factory radio.

Some C3 models have a dash-mounted CD autochanger or other features that need careful handling during the upgrade.

Citroen C3 2009 Aftermarket radio upgrade - Double DIN (citroenc3owners.com)

Professional Installation:

Consult with a car audio installer or technician to choose the best solution for your specific Citroen C3 model. Regardless of the approach you take, professional installation is highly recommended.

If the keyboard isn't faulty and is a usb keyboard, your computer should recognise it and load the driver.

If it doesn't then restarting without the keyboard and then again with the keyboard should put matters right. If it doesn't then suspect a faulty keyboard or investigate further in the device manager and use the troubleshoot option.

A din or a ps2 keyboard must be plugged in before starting the computer or they won't be recognised.

Your device has no WiFi capability so you cannot get Netflix or YouTube,on the road or at home (you can forget about finding and connecting to an OPEN Wi-Fi network on the road !). As far as watching YouTube videos on your device, there is a workaround: download the videos to your computer, transfer them to an SD card or a flash drive (the flash drive option may not work because the USB port on your device may accept flash drives only for maps or firmware updates for the GPS) or burn them into a DVD and then put the SD card/flash drive/DVD disc into the appropriate slot on your device. But I hope you do not intend to watch videos while driving !

Best to contact Aerpro www.aerpro.com.au

your radio/dash opening DIN size is what they call double DIN, to get the right unit fopr this u will need to know if you have a Facory Infinity premium sound system, it makes a diff in the model f the in dash units, here is a link to a site that has a selection of in dash DVD players for your double DIN dash.
http://www.crutchfield.com/S-nkinM0jziRR/cgi-bin/autoinfo/autoinfo.asp?id=&vehicleid=14718&vb=Y&TypeCH=&lp=%2Fg%5F168550%2FIn%2Ddash%2DDVD%2DReceivers%2Ehtml%3Ftp%3D20217&sl=Y

No, it does not.
Check the specs of your desktop PC here:

Ports and Connectors
Externally accessible:
Serial
9-pin connector; 16550C-compatible
Parallel
25-hole connector (bidirectional)
Video
15-hole connector
Keyboard
6-pin mini-DIN connector
Mouse
6-pin mini-DIN connector
USB
two front-panel and four back-panel USB 2.0–compliant connectors
Network
RJ-45 connector
Audio
three back miniature connectors for line-in, line-out, and microphone
Headphone
one front miniature connector for line-out

Ports and Connectors
Externally accessible:
Serial
9-pin connector; 16550C-compatible
Parallel
25-hole connector (bidirectional)
Video
15-hole connector
Keyboard
6-pin mini-DIN connector
Mouse
6-pin mini-DIN connector
USB
two front-panel and four back-panel USB 2.0–compliant connectors
Network
RJ-45 connector
Audio
three back miniature connectors for line-in, line-out, and microphone
Headphone
one front miniature connector for line-out
http://support.dell.com/support/edocs/systems/dim2350/specs.htm#1107078

try to barrow to your friends other battery dsame model of your phone and din insert it din try to charge and on...if your phone charging that mains your battery problem... or use other charger

CAN BE SOLVED IF YOU CHANGE THE CHARACTER CODE FOR SUBTITLE, LG= PRESS 5 SECOND ON SUBTITLE BUTTON AND SELECT ANOTHER LANG ID

USB mouse/keyboard to 5-Pin DIN or 6-Pin Mini-DIN adaptor USB Function 5 Pin DIN 6 Pin ps/2
Pin 1 +5V Pin 5 Pin 4
Pin 2 -Data Pin 2 Pin 1
Pin 3 +Data/clock Pin 1 Pin 5
Pin 4 Ground Pin 4 Pin 3
shield shield shield

they are sized by a measurement system known as DIN. Yours is either a DIN 1 or a DIN 2, differentiated by the height of opening in dash. Simply put, the DIN 2 is twice as large as a DIN 1. If the opening height is roughly 2-1/2" high, you need a DIN 1 unit. Prior to the DIN rating system, many owners were frustrated over the 'FIT' incompatibility with various widths, depths and heights.