The procedure to follow to download Snapchat for PC, is the same as is done for any program that is downloaded from the Internet. That is, you should not execute the file directly, you must save the installation file to your computer and once the download is complete, proceed with the installation of the application.
This also has great difficulty as it is done like any normal installation programs on the PC. It means that in a few seconds then start to use Snapchat from the PC without using your iPhone or Tablet. Now if you choose to download Snapchat PC via an emulator, the procedure is equally simple.
Even if you have the apk file Snapchat, you simply need to drag and drop this file on emulator interface and wait for it to automatically install the application.