It's pretty easy and nothing to worry about. You will need to sand the top down to 240 grit, wet the top to allow the grain to raise up, sand some more, wet and keep sanding until the grain no longer raises up, usually about four to six times, once the grain no longer rises up you will need to bleach with A + B ( ammonia solution + hydrogen peroxide ). neutralise the bleach with acetic acid ( white vinegar ) or just lots of water and allow to stand for three to four days, then sand down with 400 grit. You should achieve a nice burnished finish. From then on to maintain the top it will need a wipe over with a rag soaked in a weak solution of domestic bleach which will take out any stains from food or oil. I did a sycamore top using this method for a family with very young children and it survived tinned baby food felt tip pens and all sorts of abuse and still looks good twenty years on with nothing more than a bleach rag wiped over it every now and then.
regards,
mrpercysnodgrass.