Tap root normaly first then the main leaf shoot will apear.
If you want to start them off and watch ( which is very interesting) get some bean seed kitchen towel and a plastic box with fitting lid.
inside box put a double layer of kitchen towel wet it let excess drain away place seed in and cover with a double layer of kitchen towel press down so all towel is damp put lid on box.
Check daily you then will see life before your eyes the bean starting to grow.
When the tap root shows you can pot up with the root pointing down.
This way you only pot on growing beans, dud seeds which dont grow you can throw away.
Or leave untill the main stem appears and pot up or plant then as long as they get a good watering they will be fine.
I still do this after years of gardening and watching new life never stops amasing me. Great to show children
I remember doing it in school with a jam jar, blotting paper and two bean seeds. Ah the good old days ha ha.