linux installation security info

HI guys, Can anyone assit me with info regarding the installation of linux. When ever i download an iso and run a test with 7zip on the iso it always comes back with an error saying there is payload at the end of the data. Does anyone know what the standard command lines are for the bootloader when installing, I have this code, is this okay ?
if loadfont /boot/grub/font.pf2 ; then
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm
fi

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

menuentry "Start Linux Mint 19.1 MATE 64-bit" {
set gfxpayload=keep
linux /casper/vmlinuz file=/cdrom/preseed/linuxmint.seed boot=casper iso-scan/filename=${iso_path} quiet splash --
initrd /casper/initrd.lz
}
menuentry "Start Linux Mint 19.1 MATE 64-bit (compatibility mode)" {
linux /casper/vmlinuz file=/cdrom/preseed/linuxmint.seed boot=casper xforcevesa iso-scan/filename=${iso_path} ramdisk_size=1048576 root=/dev/ram rw noapic noacpi nosplash irqpoll --
initrd /casper/initrd.lz
}
menuentry "OEM install (for manufacturers)" {
set gfxpayload=keep
linux /casper/vmlinuz file=/cdrom/preseed/linuxmint.seed oem-config/enable=true only-ubiquity boot=casper iso-scan/filename=${iso_path} quiet splash --
initrd /casper/initrd.lz
}
menuentry "Check the integrity of the medium" {
linux /casper/vmlinuz boot=casper integrity-check iso-scan/filename=${iso_path} quiet splash --
initrd /casper/initrd.lz