On the readme, the is the installation procedure for Sam460ex + SD card. It says "Write morphos-3.8.hdimg to an SD card directly as a disk image". How to do this ? Simply copy the file in the SD card ? Or it needs a particular software ?

Thanks.

Please see the following page:
How to write SD card images on Linux, MacOS and Windows

Or if you want to do it on a MorphOS system:
http://library.morph.zone/Tips_and_Tricks#Copying_a_Whole_Disk_As_an_Image_File

Thank you!