Naha airport flight transfer

Hi,
Tried to find information on how to transfer flights at Naha (Okinawa) airport. I am planning on a flight from Fukuoka to Okinawa and then a flight on the same day onward to Ishigaki (there are no direct flight from Fukuoka until summer).

How do you transfer between domestic flights at Naha airport?

Do I have to exit the airport and check in again or is there any transfer desks at the airport?

Do I have to exit the airport and check in again

No. The departure lobby and the arrival lobby share the same place.

Do I have to exit the airport and check in again or is there any transfer desks at the airport?

There is no transfer desk. Just find the departure gate and stay around. I think you will get two boarding pass at Fukuoka, one for Naha and one for Naha to Ishigaki. Just hand both of them at the security gate in Fukuoka, then the staff will give you two small sheet (sorry, I don't know the name) one for Naha and one for Ishigaki. You will use them when boarding. If you are not sure, just ask the ground staff.

By "JTA to JTA" or "JTA to RAC" should be done only once.
http://www.ishigaki-airport.co.jp/en/flight.html
http://www.jal.co.jp/en/dom/boarding/onto/
BC both are belonging with "JAL" group and flight booking system including,
so you can search as "FUK" to "ISG" fr the list of airports open "H to N" then select "Ishigaki".
http://www.jal.co.jp/en/
https://i.imgur.com/362xjec.png
This is one of result, test search as dep at 18 APR.
https://i.imgur.com/R4dr8k4.png
You can see both transfer cases.
(note) 1st flight using "JAL" means back to HND(Tokyo), open "1" of "No. of stops".
Also you can use "contact form" if still wondering.
http://www.jal.co.jp/en/information/

If need more money saving, back to east KIX(Osaka) by Peach twice may cheaper, depends on date.
http://www.flypeach.com/pc/en
But in this case, you cannot search like above and be careful fee of many options.

Anyway, Naha airport is not so large, no worry.
http://www.naha-airport.co.jp/en/