How to upload a park to NolimitsCentral?

I've been wondering how to upload coasters to this website though I can't figure it out; it gives be an error that nolimits2 park files are incompatible.

Go into your editor to the park that you want to upload, then click "extract package" under the file tab. it will result in a .nl2pkg file, which you can then upload here.

Edit: Save Package, thanks MrRC

Not "Extract Package" but "Save Package"

Im running on Mac and I dragged the file into the upload box and the .nl2pkg file had an error so It couldn't upload it.

thanks I will start uploading soon! :)