Be sure to download the PDF Manual from Nikon
so the search function works.
Start on page one
Sit in front of your computer, with your new D5300 in hand.
Don't hesitate to set Auto ISO to 12800
The stills and video above ISO 3200 are noticeable better than any other Nikon DX including the D7100.
I've owned or used nearly every DSLR that Nikon has made including all the heigher end ones but the new DF.
But, it is FullFrame and does not do Video.
Speaking of which, The 1080P 60 videos are the best I've seen.
No, I do not use that setting to get slow motion, I can do thatto any video file with VLC media player.