Hi and welcome to the forum!
You didn't say where you are located. here are hardly any garden questions that can be discussed without regard to location/ climate.
But you did well to write in right away. Your juniper does not look very bad so far, should be salvageable. But yes, junipers DIE indoors. Especially if you are somewhere where you already have your heat on, indoor air is warm and very dry. That is why it is starting to brown.
And junipers need cold dormancy. It needs to rest outdoors. If you can keep it alive through the winter indoors with misting and lighting, then it will die next year from not having had the dormancy.
Don't water it on a schedule. Water it when it needs it. If it is dormant outdoors, when it needs it will be very infrequently.
Do some reading about bonsai care. You can start here: https://www.helpfulgardener.com/bonsai/
and with some of the articles at the top of this Learning Library section.
If you want indoor bonsai, look for ficus and other tropical evergreens. Plants in the tropics are adapted to year around growing. Temperate climate trees are not.