The online manual explains the process here
. However here are some notes for you:
1. .zip files exported from FL Studio Mobile will also contain any custom instruments and audio files. Image-Line factory instruments are not included in the .zip and need to be downloaded through the Download & Library manager.
2. To open FL Studio Mobile .zip projects directly in FL Studio for Windows, prior to 11.0.5, you will need to extract the .zip contents to a browser visible location before the project will load. After 11.0.5 you can load the .zip file as is.