I recently purchased the Oscar Schmidt og10cefys folk acoustic electric guitar, it came with a 9v battery, but when I try to turn it on nothing happens. Is the guitar supposed to be plugged into an amp for it to be turned on? I'm just trying to use the tuner on the guitar. Thank you

I am no expert about such things but the electric guitar pickups work with steel strings, wouldn't work if the strings weren't steel - the pickup is a coil of wire and the vibration of the steel string generates an output in the coil the amplifier can work with.

The pickups of the acoustic guitar are presumably glorified microphones that would usually work in a similar fashion to the above, by generating an output but if they are active devices they will need a power supply in order to generate an output, something a standard amplifier input will not provide.

An active device either needs an independent power supply to make the device work like a radio needs a battery or the device will create the output by varying the current flow of the voltage applied across it.

Serial number: 82559520
Production year: 12 September 1989 (serial nr.: 520)
(Manufactured if Electric: Nashville or Memphis. if Acoustic: Bozeman, Montana.)

According to Guitar List: "Ariana is an entry level brand of the Aria company. The Ariana brand has been around since the 1970s and there are Ariana electric guitars, acoustic guitars and folk instruments. These instruments are made in the Far East (including Indonesia)." More here...

https://www.guitar-list.com/brands/ariana

$100 and up depending on the condition and who your getting it from.

It is easy to replace the battery in your Washburn guitar.

The battery compartment is located where you plug in an instrument cable to your guitar. Simply open it and take out the old battery and put in a new 9V. battery.

Regards

That is working backwards from what it should be. I suspect a wiring error. Since this is a recent purchase, do NOT risk voiding your warranty. There isn't any real good documentation on the tuner.
I am not sure which tuner you have HOWEVER with one type, the FIRST press will turn on the tuner with the sound going out as well till the tuner goes off. The SECOND press silences the sound and is tuner only, the THIRD press turns off tuner and passes the sound. This is different than a lot of tuners and you will need to do three presses to restore sound instead of the usual two.

Replace the battery. Batteries tend to recover and then go down again when they get weak. Use GOOD alkaline batteries NEVER rechargeable types.

Try a guitar repair shop... they MAY have salvaged parts from another damaged tuner.

If it is an APX-500, the battery is in a holder between the neck and the tuner on the curved sides of the guitar. It should unlatch. The battery (9V) goes into the holder and is inserted and latches.