There does not appear to be, at the time of writing, a way to install ToolBox or WebStorm from apt-get. So, we will have to do it the hard way. Go to the ToolBox download page at https://www.jetbrains.com/toolbox/app/ and download the Linux tarball. Then, open a Terminal to your download directory. Once there, execute the following commands:

mv jetbrains-toolbox-<version>.tar.gz <application directory root>/jetbrains-toolbox-<version>.tar.gz
cd <application directory root>
tar –xj jetbrains-toolbox-<version>.tar.gz
chmod –R 777 jetbrains-toolbox-<version>
cd jetbrains-toolbox-<version>
./jetbrains-toolbox