Yes you are using 64-bit right [as the flasher you have downloaded is 64-bit]? Just double click on it and if you are using Ubuntu it will open Ubuntu Software Centre to install it...

if you do it via terminal just dpkg -i /path/to/flasher*

flasher gets integrated into the system unlike windows so you won't have to cd to flasher's directory after installation just need to cd to where the kernel and initrd are downloaded to [most likely /home/USER/Downloads/]...