Hi @grahamUTKMN
I hope you are doing well! For all you questions, here is my answer.
Q1: Step 4 says: Leave the Location field blank for now, or click the arrow on the right and select a project for the file.
I don't seem to have the option to leave this blank, why not?
Answer: I think the meaning of 'Leave the Location field blank for now' is that you can just leave the Location as it is now (The original Location is the opening project path in the data panel ). If you don't want to save your electronic design in the path, you can click the arrow on the right and select any project you want to save the file.
Q2: What am I actually saving here, is it a project file?
Answer: You are saving the whole electronic design in this step. The schematic and board file (and 3D PCB) will also be in the electronic design. So if you save the electronic design, all files (schematic,board,3d PCB) will all be saved.
Q3: Do I HAVE to save it in the cloud? Can I not save files locally any more?
Answer: I may misunderstand the 'Have to' here. For me, I think it is better to save the whole electronic design in the cloud. It will be well saved and managed when you save them in cloud. You can see your designs when you log in Fusion 360.
If you don't want to save them in cloud, you can also export the schematic and board files. Personally I think it may not a good workflow to managed all your files.
When you save your electronic design in the cloud, you don't need to save the files locally unless you have other need.
Q4:My actual schematic and board files are still going to be stored locally on my machine, why are things split up?
Answer: I am not sure the meaning of this question. Do you mean that you want save files locally? If you want, Fusion 360 also supports exporting the files in local path. If I misunderstand something here, please let me know, thanks!
Q5: If it is a project file, and I do have to save it in the cloud, how does this all work if I then want to edit my design in the future in Eagle? Is that all ok?
Answer: If you want to edit your design in Eagle, you can just export your schematic and board file as .sch and .brd files. Then they can be opened in Eagle successfully.
I hope my answers can help you a little. If you still have other questions, please leave your comment, thanks!
Regards,
Panpan Fan