As a newbe with a new Yaesu FT-70D, on 3/16/2019 I used CHIRP to easily import into it the 43 repeaters within 20 miles of me, per RepeaterBook.com.
I first installed a virtual com port to my Win10 laptop using:
https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers
I first manually programmed two repeaters into my FT-70D so I'd have some data to view.
Then I ran the CHIRP program, following its on-screen instructions to connect my HT.
Using the CHIRP program, I then imported my area's repeaters.
Then I exported the data so I could use Excel to re-arrange the rows.  Having the data in Excel allowed me to print a list on paper, that I now refer to.
Then I imported the data back to my FT-70D without problems.

FWIW, on the "Official Yaesu USA" Facebook group site, the Yaesu nat'l sales mgr, John Kruk, on 3/12/2019, responded to a comment, "Is there a problem using chirp?" by writing "Yes CHIRP has damaged radios".  Perhaps someone had tried using CHIRP with an unlisted radio or had failed to follow the CHIRP instructions.  I discovered Mr. Kruk's comment after I had successfully used CHIRP.

Thank you for the volunteers who developed and maintain CHIRP!

Doug K7KDG