How to open a PDFs in iBooks?

[blackxacto]

iPad Air w ios9
iMac w El Capitan

I don't want to go to my iMac, but use my iPad Air only.

From my iPad Air, I find a file on my iMac and send a copy of the file to Google Drive. Now, my question: how do I open the file in iBooks on my iPad Air?

Yes, if I go to the iMac and manually sync the PDFs to my iPad Air I can do this, but how do I do this ONLY from the iPad Air? I just want to open the file in the iBook iPad Air app.

 

[lagwagon]

iPad Air w ios9
iMac w El Capitan

I don't want to go to my iMac, but use my iPad Air only.

From my iPad Air, I find a file on my iMac and send a copy of the file to Google Drive. Now, my question: how do I open the file in iBooks on my iPad Air?

Yes, if I go to the iMac and manually sync the PDFs to my iPad Air I can do this, but how do I do this ONLY from the iPad Air? I just want to open the file in the iBook iPad Air app.

I don't know if it's something new to iOS 9.3 but for a couple seconds once going to a pdf in Safari there is a bar at the top that lets you open in iBooks. (I have no clue how to make the button reappear once it fades away other than reloading the page.)