Remember that Lertap 5 is an "app" which runs with Microsoft Excel. Your computer must have a copy of Excel in order to be able to run Lertap 5. Excel is part of the suite of programs which Microsoft refers to as "Office". Other apps in the Office suite include Word, Access, and PowerPoint.
Windows users with Excel 2010, Excel 2013, or Excel 2016 may download Lertap 5 from this link. You'll note that the downloaded file will have a name similar to "SetupLertap51084.exe". This is what's called an "installer file"; in this example, the Lertap51084 part of the file name means Lertap 5, version 10.8.4.
The installer will see to it that your computer is set up to run the free "Mini Version" of Lertap 5, a version limited to processing no more than 100 data records. This limitation may be overcome by the purchase of a license from the Store. (The topics immediately following this one have quite a bit more to say about installation and licensing.)
Users of Excel 2007, an older version of Excel for Windows, may download version 5.8.3 of Lertap 5 from here.
If needed, and if you're working on a Windows computer, follow this link to help identify the Excel version running on your machine.
To get a copy of Lertap 5 for a Macintosh computer, please write to email@example.com and request instructions. As of June 2017, the Mac version of Lertap 5, version 184.108.40.206, was working only with Excel 2011 (not yet with the Mac version of Excel 2016).
The next topic gets into matters related to installing Lertap 5 once the installer package has been downloaded.
A document covering the on-going development of Lertap 5, with version numbering, is available here.