I just got a pet rat and im confused.

Question
I got a female rat.She's the first rat i have ever had and i need help.Before i got her i did alot of research on rats,like all pet owners should do,and it mentioned that rats are supposed to use the bathroom in one corner of their cage.I have had her for a week or two now and she doesnt use it in the corner and my grandmother is concerned and so am i.I also read that rats love to play and are easy to train,but she won't play or train.I don't know if i'm just not doing something right or if it's just her.I bought her some toys(balls,chew toys,etc.)but she won't play with them or even play attention to them.She plays with me and that's how i know she isn't scared of me but i don't know what to do.
           Before i got her i bought an aquariam and set it up with a screen top but she always stinks.Am i using the wrong type of habitat?I also don't know what type of bedding or flooring to use in her aquariam.The pet store i got her from tryed to talk me into getting pine flooring but i read that it is bad for the rat so for now i am using inkless copy paper in the bottom.When i got her and brought her home, she was sneezing and wouldn't  stop and she has stopped a little bit but not compltely.My grandmother told me when i got her she is my responsibility and I respect that but I don't know what is wrong with her please help.
                         Thanx very much,
                              Cayla age 13

Answer
sorry for the late response I have been very ill,

some rats just dont have in interest in toy, no big deal, rats dont alway poop in one corner, none of my rats ever did and I have 16! the tank is fine, but it will smell more because it is in a tank. just wash it once a week.