Problems running makefile in Ubuntu

Hi. I am trying to run the makefile of ble_app_blinky (from SDK 15.2.0) on Ubuntu 18.04 and Visual Studio Code. When running "make" in the armgcc directory, the following error appears:

"make: /usr/local/gcc-arm-none-eabi-6-2017-q2-update/bin/arm-none-eabi-gcc: Command not found
Cannot find: '/usr/local/gcc-arm-none-eabi-6-2017-q2-update/bin/arm-none-eabi-gcc'.
Please set values in: "/home/david/Documents/Nordic_BLE/nRF5_SDK_15.2.0_9412b96/components/toolchain/gcc/Makefile.posix"
according to the actual configuration of your system.
../../../../../../components/toolchain/gcc/Makefile.common:129: *** Cannot continue. Stop."

Previously I successfully run the following command: sudo apt-get install build-essential
However, there seems to be something missing...

I am new to Linux/Ubuntu. Can you help me?