There's a little leaver that locks the shifter, remove the boot around the shifter and push back the leaver with your finger. If there isn't any battery in the car it will not move it, even if you turn the key.
If you have a good working battery, you should be able to turn on the key, apply the brake, & shift.
If it will not shift with a good battery, you can remove the boot & disconnect the shift lever tab as stated above.
If you have a good working battery & you still cannot shift after applying the brake, you could be looking at a faulty Brake Light Switch.
Just thought I would trow this out as a possible cause, for search purposes.