If you downloaded a SKP file on Android device you can open it by following steps below:

Install the application you found and check if it can read SKP file.

If you don't know the application which can open SKP file then try to search for 'SKP viewer', 'application to open SKP file' or 'read SKP file' queries in the online search engine you like.

If you know the Mac OS application which can work as SKP file opener you can choose the 'Choose Application.' option in the error box to associate the file extension and open SKP file in it.

If a SKP file is not opened in a Mac OS application and you instead get a 'There is no application set to open the file' error message you can click on 'Search App Store' in the error dialog and Mac OS will show you applications compatible with SKP file.

Find a SKP file in question in Mac OS Finder and double click on it to launch the corresponding application.

Install the application you found and check if it can open SKP file.If you don't know the application which function as SKP file opener then try to search online for 'SKP viewer', 'application to open SKP file' or 'open SKP file' queries in the search engine you like.

If you know the application which can open SKP file then run it and see if there is a File->Open main menu option in the application.

If a SKP file is not opened in an application and you instead get a 'Windows can't open a file' error message you should try looking for an application which can open the file in question.

Find a SKP file in question in Windows OS File Explorer and double click on it to launch the corresponding application.

Skp viewer online