After installing Squish IDE I get a window that asks for the location of Squish tools. I can't get past it, because the OK button is always disabled and when you click cancel the program exits. I also don't find any tools packages on their website.
Select Squish Installation Folder
The specified Squish Tools package does not contain the squishrunner tool.
The Squish IDE that you are installing requires the Squish Tools which are supplied as a separate package. If you have already downloaded the Squish Tools package (whose name begins with "squish-"), simply choose the folder where the Squish Tools were unpacked and continue. If you have not yet obtained the Squish Tools package simply download it from your customer download area and unpack it into a folder of its own. Then choose that folder and continue.
The Squish IDE is just a wrapper around the Squish tools. Usually one downloads a Squish package like squish-6.x-qt513x-linux64.* (for Squish for Qt for Qt 5.13.x for 64 bit Linux) or so, and these packages include the Squish IDE and the tools and support for that GUI toolkit.
Squish technical support may suggest to use the separate Squish IDE packages for some reason, but that is the only time you should be using them.
I recommend to ask your colleagues for more information on how to proceed. You can also contact Squish technical support who can tell you (based on the Squish editions registered for your email address) which packages to download and possibly also how to proceed.