Hey.
its basically just like how you use aff, but i gonna admit lj is a bit difficult...
like any other website, first you have to log in into an account. so, if you don't have a lj account, make one.
go to her ff page, which i believe is homeofyunjae.livejournal.com
then add her as her friend, you need to wait for her to accept your request and add you back as a friend. and also, you need to post a comment on the fic list comment section, ask her to let you join and add you back as her friend. once she added you back as her friend, you could read her fics.

But the thing is, according to her latest blog post, she haven't finisih moving her fics to lj, and probably would be coming back here, and i added her sometime ago and she haven't added me back, so i don't think she is adding anyone at the moment, probably still busy moving the fics there... but you can go ahead and try.
please tell me if you got any response, i will send another request to her. i love her fics too! :D i wish she would be coming back soon....