Imagine you have to climb a mountain carrying a really heavy backpack. You'd get tired and fall, right? But if dad is right there and says, "Give me the backpack, son," you'd climb up running and happy!
"Committing your plans" means handing the heavy backpack to God. When you have a hard test or are scared of something, don't try to carry it alone. Say: "Father in Heaven, will You carry this with me?" Then everything works out, because God is the strongest in the whole world!