What is the first thing to do for someone who appears to be choking?

Encourage the person to keep coughing to try and clear the blockage.
Ask the person to try to spit out the object if it's in their mouth.
Don't put your fingers in their mouth to help them as they may bite you accidentally.

If you are experienced, you should help them. If you are inexperienced, get some help so you don't make the matters worse. Better safe than sorry, a quote that helps many people, including me.

Hope this helps!!

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.