You can find the guide here>>6422
It's in the first Mega link, once you open it, you will find this file called "How to import models.pdf", the name means that it teaches you on how to import models, the process of converting a PMX file to a GTS.
And just below there is this "Model Importer" file, the name is in English and means that it contains the most important part of the process, you can find the instructions on the "How to import models.pdf" file, the name means that it teaches you on how to import models using the "Model Importer" seen before.
PDFs are usually open with the Adobe Acrobat software, and is a free software, you do not need to pay to use it.
7zip files can be opened with either 7zip, a free software, otherwise you can download and use WinRAR, which will ask you to buy in 40 days, but can be used with no limits anyway.