This application does not exist anymore on latest version of Ubuntu.
usb-creator is installed by default in Ubuntu 24.04, see https://releases.ubuntu.com/noble/ubuntu-24.04.1-desktop-amd64.manifest
I tried to use the one when launching the disk app but I didn’t succeed in making it work. Is there some command I can enter to create a specific icon on my desktop?
If you installed a minimal Ubuntu desktop system, you must install the Startup Disk Creator separately,
sudo apt install usb-creator-gtk
What distro/version did you try to install and which iso file did you use? Did you check (with a checksum) that the iso file was downloaded correctly? Did you unmount all partitions on the target drive?
If still problems, you can install and use mkusb.
I get a Malformed entry 1 in sources file /etc/apt/sources.list.x/third-pablabla (URI parse). I use the last version of Ubuntu.