[Eric Santiago] “I can’t seem to figure out how to use frame io as an export option from the timeline.”
If you have FCPX 10.4.2, you need to update to frame.io v2 (via App Store).
There is an option to install the Share Destinations in to FCPX.
If you have already done all of this, then use a share destination, set your settings for encoding, and click Export.
You get the resulting dialogue box, be sure to click “Clips” at the top.
Similar process, different look.
Here’s a picture:

Jeremy