The hands are so important in the front crawl. Every body part has a place to be, but usually that positioning has to do with keeping that thing out of the way to reduce drag. The hands and forearms are where the actual thrust comes from, so how you move them through the water really matters. First, when your arm swings over and is about to enter the water, keep your wrist loose and just place your hand in. Once your hand is submerged and you start pulling, you need to begin engaging the hand and wrist for the pulling phase of the stroke, but until then keep it relaxed. This minimizes the drag that your hand produces as it enters the water.
Once you start pulling, keep your fingers together so your hand forms a cup shape. If your fingers separate, water can pass through and you lose out on a lot of thrust. Like the end of a canoe paddle, you want your hand to make as large and flat a surface as possible. When I first started working on that I noticed the tendons on the outside of my wrist getting sore, because my outer two fingers weren't used to pushing so hard against the water. But that passed quickly as the tissue adapted to the more athletic position.
A word about learning new swim technique: work on one skill at a time. It can be overwhelming to think about hand position, body roll, pointed toes, kicking from the hips, etc, constantly. So do drills where you just focus on one element at a time. With enough repetition, that particular action will get stored in your muscle memory. Then the next time you get in the water your body will automatically perform the action, and it won't require your constant attention. The good thing about endurance sports is that they involve a lot of repetition, so you should get plenty of practice. When you feel that you have that skill down move on to another skill and repeat the process.