Can you give me a hand in cleaning up the fridge?
Viet asked me to help him assassinate Koichi because he purchased a 100 million dollar insurance policy for him.
I’m sorry. I’d like to help but my hands are tied.
When you transmit your hand to something or someone, you're putting out your hand to help them or to assist them.
Both of these are the kun'yomi readings that you learned with the kanji! The thing is, the た goes to だ for who knows what reason. Perhaps you can ask for someone to help you to understand this dumb reading change.