No worries... Ok, gently hold a guitar pick in your right hand while seated at the guitar, in classical guitar seating position, wrist as I described above. Allow your fingers to curl naturally, and hold the pick gently with your thumb against the side of your i fingertip. Now drop the pick but allow your fingers to stay in that position, including your thumb. Now move the fingers toward the heel of your palm. Don't tense your fingers; just allow this to happen. That's the best I can describe the movement: yes, the last joint curls a bit, but the driving force of movement is from your knuckle, and the fingertips follow through. Pogmoor above described it well. Ultimately your fingers return to neutral position, but never "lift" toward the horizontal plane in any joint.
Also, no censure meant here, but have your considered the classes here on Delcamp? If you can't get access to a teacher it's the next thing to try. See the top of the home page, there's instructions on how to register. You will benefit tremendously from being able to see the hand position, and thus feel it -- a far better way to retain muscle memory. Mechanics/ergonomics are very, very important, yes, but to feel it for yourself is key. Best wishes and good luck!
2015 Connor spruce/Indian rosewood
1978 Ramirez 1a cedar