How to take care of 7 and 5 year olds?

My 7 yr old nephew and 5 yr old niece that I have never met are coming from about 11 hours away to live with my husband and I. They have been in the foster care system for about 2 yrs now, and we had no idea they even existed. I am very excited, and happy to get them out of foster care but I am also TERRIFIED. I don't know how to take care of these kids! What do they like to eat? Do they bathe themselves? Should I buy clothes and toys before they come? What do kids their age like to do and play with? What should I ask them to call us? What if they don't like us? I just don't want to mess this up because we are the only family they have that are stable and able to take them in. Help please!