There are 5 key areas in your profile where you'll want to plug your keywords. The first three are visible in your Headline. These are shown in the image below as the main headline; your industry (next to geographic location); and current/past employment position titles.

You can see my keyword "sports" is found in my headline, my current employment twice, and potentially, even in my past employment if I had wanted to do that as well (it will help you rank for that keyword).

The other 2 places that really matter are in your summary copy (we'll work on optimizing that next, I just highlighted my keyword "sports" to showcase how it works in mine).

And finally, the last place you'll want to make sure your keywords are present is in the "Experience" section in job titles (if possible) and descriptions. I've gone ahead an highlighted my keyword to make it easy to spot.