You can download the latest GISquirrel installer on this page, either to evaluate the product or to obtain the latest version if you hold licences. GISquirrel will run in evaluation mode until you purchase licences and enter your registration code on each PC. Evaluation mode is limited to 10,000 features per feature class, and 20 minutes use per session.
The downloaded zip file contains two files:
Extract these files from the downloaded zip file, and run "setup.exe" to install GISquirrel. This requires administrative rights on the PC.
Please read the Installation Guide and the Key Concepts section - these will help you get started quickly with GISquirrel. You may also be interested in the version history to see whether you want to upgrade to the latest version.