There are slightly different flavours of OTA. I normally use the webserver variation where the esp8266 is running a server which responds to browser access to something like http://ip/firmware which then allows selectin a binary to upload and flash. You can produce a new binary from the Arduino IDE (export binary).
The only caveat is that any new sketch you load must also contain a working OTA. If you have a separate dev environment then it is good to test that the ip/firmware link is working on any new sketch before uploading via OTA to a built project.