According to the webpage, you will be purchasing 2 versions of the Modern Apartment - Bedroom, one for Poser, and the other for DAZStudio. If you are only interested in Poser then you will only need to install the Poser dedicated files. Meaning, you do not install the DS version unless you have DS installed. Purchases like these will have those zip files clearly labeled. As mentioned in the post above, examine each compressed folder carefully before installing any content to your runtime. Folder hierarchy is very important, and anything that is out of order will potentially cause errors; that are applicable to both Poser and DS. I would suggest opening a Poser runtime folder and compare it side-by-side with your zip file, noticing the structure of all your major folders. By doing this, you will have some knowledge on how to approach the installation, whether you use the Poser zip decompression feature or manually move your content. Not sure, screencap your question.