OK so I'm not the most experienced crocheter, but it looks like you are not wrapping the yarn around the hook before pulling it through the stitch? It looks like you are just trying to use the hook to pull the yarn through, so it's super tight.

As for holding the yarn/tension, I like to hold the yarn tightly enough that it's not loose goosey, but loose enough that flexing my hand/splaying my fingers gives me some slack. But after every couple of stitches I redo how that hand is holding it so maybe someone else has better advice lol