This is just a quick utility to see exactly what is in a binary file.
See the byte2hex utility to create a hex text file that can be edited and converted back to binary.
See the HexTools utility in GnuWin32 for a more feature-rich version.
If you don't want to install anything, try the online version of HexDump.
This is a command-line tool. If you don't know what this means, this probably isn't the right tool for you.
It just takes a list of files and dumps the contents in hex on stdout.
The format is <offset (in hex)>: <hex bytes> <ASCII values>. Only alphanumeric ASCII values are shown: everything else is shown as a period (.).
For example:
hexdump myfile1.dat
There are no options.