First, navigate to your project's edit page.
Then open the BCF tab, if you already have BCFs, you will have to wait for them to load, a progress bar will indicate where the process is currently at. Once the tab is loaded, click the Import a BCF button.
Select the BCF file you wish to import, either by clicking the button and finding it on your computer or by dragging and dropping it directly onto the button.
Your BCF has now been imported, to learn more about the ways to edit the annotations, visit this article.
If you have any problem or difficulties, please do not hesitate to contact the platform's team.