Losing my dens leaves

[amleeco]

Hello everyone! Im a newbie starting out with my first den I bought from Trader Joes. Its beautiful! And I hope this turns into a long enjoyable hobby.

The tag on my orchid said dendrobium Klein - Im pretty sure its a hard kind of orchid after reading some of the forum.
But its losing its leaves! The bottom most leave on the stalk will turn yellow and the then fall of then the next in line will start doing the same. It was happening very fast at the beginning and now seems to be slowing down. Im wondering if it is going into a rest and this is how rest begins.

Also i was wondering about light, its in a window that doesn't get direct light, is that enough? Im a little confused about plenty of sunlight but not direct.

Ill try to attach its pictures. Thanks for any help!