edharman

Copy and save both install.sh and opencv4_install.sh to your home directory ~/
make them executable - 

chmod +x *.sh

You may wish to edit the opencv4_install.sh to reflect any additional components you may wish to configure e.g. GPU options.
As-is this should work ok if you have an Intel Iris enabled CPU, if you use Nvidia you'll have to google for specific instructions.
Also you can optimise the number of threads used for the compilation by adjusting the line -
make -j4
to -