Download the "Weblaunch+Setup+3.4.2-universal.exe" file and open it.
You may get an error when opening the installer. The only way for us to remove this warning is to pay over $100 per year for a "code signature". Weblaunch is still a very secure application regardless of this warning.
To bypass the warning click on "More info" and "Run anyway". You should only need to do this once.
Some anti-virus services may also mark Weblaunch as a security risk, because Weblaunch is not a well known application.
You should now have Weblaunch in your start menu. The installer may be deleted. Weblaunch will auto-update on startup if there is a new version available.