If you downloaded the zip file, please unzip it rather than clicking into it to open the .ino. it won’t be able to find all the others unless it is fully decompressed.
@Orob is right, this issue comes up a lot and it’s almost always caused by the file needing to be unzipped. It’s possible this is something new, but I would try starting fresh and be sure to open the the unzipped one and not the zipped version
i did a hard reset on my computer and started from step 1 kept having the same problem i think i wasn’t opening the unzip folder once i found it it worked thank you