On the iPad
In the Settings App iCloud pane, you need to have "Documents and Data" turned on.
Tap the settings icon in the upper right corner of LXBeams' plan screen. From there, select "Preferences" and turn on the "Use iCloud" setting. This causes files that you create on the iPad to be put in iCloud rather that the iPad's local storage.
To get a LXBeams documents folder created in iCloud, you have to create a file using LXBeams on the iPad with the "Use iCloud" preference turned on.
You can create a document in iCloud by tapping the Files button in the upper left corner of LXBeams' plan screen.
Then, either tap the "+" icon to create a new document or the duplicate icon to copy the current document into iCloud.
Once iCloud has syncronized across devices, you can procede to the Mac part of using iCloud with LXBeams. This usually is fairly quick. But, depending on the network connection to the iCloud server, it may take a few minutes.
On the Mac (OSX 10.
In the System Preferences iCloud pane, you need to have "Documents and Data" checked
In the Finder, hold down the option key and select "Library" from the Go menu
Find the "Mobile Documents" folder
In there you should see a folder with a name that includes
com~claudeheintzdesign~lxiseries~lxbeams
Inside that folder should be a folder called "Documents"
You can move .lxxplot files to and from this folder and they will show up in iCloud on the iPad
If you make an alias of the ...~lxbeams/Documents folder and rename it something like LXBeamsPlots and move it to your Desktop or Documents folder, you'll be able to open and save to and from it with LXFree or LXBeams.