One you have this, copy the file to flash using a TFTP server. Then rename the file to remove the version number, then make a backup of the configuration file just in case and reboot the router. The reboot should force the new firmware to be loaded. Once rebooted verify the version of the firmware
Check the version of the firmware current running
show dsl interface ATM 0
Init FW: init_xxx-x.x.xxx.bin
Operation FW: xxx-x.x.x.bin
FW Source: xxxxxxxx
FW Version: x.x.x
Check the amount of space available on flash for the firmware, ensure that the bytes free is greater than the size of the firmware .bin file
show flash
19353600 bytes total (5369856 bytes free)
Copy the firmware .bin file to flash
copy tftp://xxx.xxx.xxx.xxx/adsl_alc_20190.x.x.x.bin
Rename the file on flash to adsl_alc_20190.bin
rename flash:adsl_alc_20190.x.x.x.bin adsl_alc_20190.bin
Reboot the router
reload