Hello, Pierre -
Apparently you do not have the user manual for your Tom Tom.
You have not stated the model name of your Tom Tom.
Therefore, all I can do is direct you to the Tom Tom home page:
On the home page, you should see the link to Support, located near the top of the page.
Click or tap on Support. You then should see the link to User Manuals. Click or tap on that link.
Then you will land on the User Manuals pages (more than one.) You will need to find the link for your model Tom Tom (look through the User Manuals pages), choose it, and follow the on-screen information to download the correct manual (probably a PDF document - Adobe Acrobat Reader software needed - free) and save it to your computer. Note: If you do not own a computer, ask a relative or friend if you can use their computer to download and print the manual. If you need to do that, I recommend you give the relative or friend a ream of printer paper as a "thank you." You may also wish to purchase a black printer ink cartridge (make sure you know the manufacturer and ink number used) as a "thank you" gift, as well.