1. Export the project from GDevApp and open it in GDevelop, The events should load fine then you can either copy the events or just continue using the GDevApp project inside GDevelop. The trouble is, when you download a project from GDevApp, the images are not included and also the path of the images need to be edited after import in to GDevelop. With big projects with lot of images, it a pain but for simply getting the actual events from the project it could be useful.
2. You can also try the event store. It is not meant to be used for sharing the code of complete projects but in theory you can just share the code in the event store and import it in GDevelop. But last time I tried the event store importer didn't worked very good in GDevelop. The events I tried to import was broken. Variable and Object names was missing, values of variables was missing..etc it was a complete mess. So at the moment I don't think the event store is a realistic option but it there, you can try.