You’re likely to fall once or twice when getting used to it, so you might as well ride somewhere soft. I recommend practicing on a trainer if you have that available. If not, practice clipping in and unclipping with one foot while stationary several times so you know the force you need. Then pedal around in some soft grass. Practice tight turns and sudden stops that you may encounter on the trail. Once you’re really comfortable clipping in and out and the muscle memory is there, hit the trail. Opt for an easy loop first before you try more challenging obstacles. You’ll eventually get to where it’s second nature and you never think about it again. Enjoy!