First thing I would do, is check the Atic floor can take the weight.
Buying wood in small quanties, such as the 15kg bags is an expensive way of running it, if you are planning to have it going most evenings this time of year.
& a new user/burner uses a stack of wood in the first year 😉
I burn evenings only & get through 2 tons of seasoned wood a year, which takes up quite a bit of space, more than you think anyway.
Collecting wood is very addictive, once you have a burner to play with 😉
[edit]Ash is king if you can get it…