Good morning, Pelouk. Let me try to be of help.
First, you need to move your .ISO file to some folder in your hard drive. You must also move or backup any other important files you may have in the USB flash drive.
I'm assuming that you are doing this in Windows, and have the USB flash drive inserted.
Second, let's work on your formatting issue:
Open Windows Command console by typing  
cmd  and right-clicking on 
Run as Administrator.
Once in the console, type  
diskpart  and press [
Enter]
At the prompt, type  
list disk  ...press [
Enter]
It will list the disks available on your system.
CAREFULLY, find the disk number for the flash drive where you'll install L.L., it will be listed as something like "
Disk 2  Online  7606 GB" or something similar. Take note of the disk number, it should be 
Disk 1 or 
2 or 
3, etc, depending on how many you have set up on your computer.
NOTE: Usually "
Disk 0" is your main (system's) disk, so 
don't mess with it.
Once you've made sure of your flash drive's disk number, double check it.  8) 
Now enter the following (substituting the number for the actual flash drive's number):
sel disk 1     ...press [
Enter]
...this means "
select disk 1" to work on it. The number 
must be your actual flash drive's number.
When it prompts you that the disk has been selected, just type  
clean  ...and press [
Enter]. (This will completely wipe out any partitions on the flash drive).
If successful, type  
create partition primary  ...and press [
Enter] (this will create a new unique partition on your cleaned USB flash drive).
When successful, type  
format fs=fat32 quick   ...and press [
Enter] (this will format the partition to the universal fat32 format, and it will do it fast).
If successful, type  
active   ...press [
Enter] (this will mark this partition as an active one).
When successful, type  
exit   ...press [
Enter] and close the window.
Now, to copy, or "burn" the .ISO image of LinuxLite to your flash drive, the most efficient smallest simplest fastest portable application to do this, is:
USBWriter-1.3 ( 
https://sourceforge.net/projects/usbwriter/ ) download it and run it, upon running, it's usage is self explanatory.
         - * - * - * - * - * - * - * - * - * - * - *
Now let's assume you are doing this from within Linux, just download Etcher and run it, it is very user-friendly.
Cheers, my friend, and please tell us how it did go.
	
Pathological tweaker.