Put chicken pieces into the inner pot of the instant pot. (If you choose not to brown the chicken, then the first step.)
Put in garlic, honey, soy sauce, ketchup if using, water, dry oregano into the pot.
Mix everything well, be sure all the chicken is covered with the marinade.
If you choose to cook root vegetables with it, put them on top of the marinated chicken.
Close the lid of the instant pot.
Set the venting knob to sealing (not venting).
Set it on Manual High Pressure for 10 minutes.
Natural release for 5 minutes. (natural release means once the 10 minutes cook time is over, do nothing for 5 minutes, and you'll see the counter on the display counting up 5)
At this time you could decide whether you want to do a natural or quick release for the remainder of the pressure.