Just pinch off the browned tips,mix some fertilizer into the next watering,and relax...
Junipers are amongst the easiest bonsai to grow.
You should find a somewhat deep saucer and water it from below,like an african violet,and use a water soluble fertilizer at 1/4 strength once in late spring.

Hi - your tree may be gone from all that watering. Tags are notoriously one size fits all and they should be thrown away (whatever the plant name printed on them). You haven't said if there's a layer of glued on rocks on top of the soil (it should have been pried off day one), or if the mix is obviously mostly grit, or more regular looking brown soil (which is the other half of the mistake with most inexpensive store bought bonsai), because it's usually 'potting soil' and full of water holding peat, guaranteed to rot roots. You should (though had no way of knowing - which is why bonsai should never be gifts unless the giftee is already knowledgable) have repotted into an almost completely grit mix with some pine or fir bark mulch but no potting soil, which would let water run right through the mix without damaging anything, only allowing a 'drink' to all roots - and always water from on top with any trees - they're NOT African violets! Plus regular house plant fertilizer can be used, regular strength, except from late summer through fall, when a very low nitrogen type is needed. Anyhow, once a juniper's foliage is mostly brittle (and brown) it's usually long gone - different from if only one branch is a problem, so you'll have to judge that.