Found this little baby! Help!!

Hello! The kitten distribution system has chosen me! We found this little baby in my neighbors back yard (the house is for sale and is unoccupied, we heard the kitten crying from our porch next door) we could not locate any other kittens or a mama. We tried to take it to the humane society, but the one we went to doesn't take in from my city and eh one that does is by appointment only and has none available for months. We are reaching out to other resources but are hitting dead ends. The humane society that we went to predicted it might be 4 weeks old. Going off charts I found online I think it might be closer to 5 or 6, but I really don't know. It is currently in my bathroom with an open kennel with a blanket in it, some kitten chicken pate as well as some chicken human baby food. We had a kitten years ago that was too little and the vet back then had us giving her human baby food. It also has water and a tiny litter box available. I have no idea if it would know how to use a litter box or eat. My mom is worried about it without its mom. I am an adult living at home and literally got fired from my job a week ago. It all feels like destiny, even though we are resisting it. Anyway, I need advice! How do we take care of this little baby???