Yep keyword research and meta keywords are two different things.

The idea behind keyword research is you need to research what words and phrases your customers and clients use when searching for your products and services. A good example is mobile phones. Companies used to refer to them as cellular phones where their customers called them cell phones. You want to use the words your customers use, because that's what they type into search engines.

If you sit down and brainstorm you can probably come up with a list of 50 - 100 phrases people likely use. Think phrases over words. You wouldn't target the single word mobile since it can mean so many things, it'll be harder to rank well for, and most people using the word probably aren't looking for what you have. Better would be mobile app development. Read the PDF I linked to above. It's not very long. It's about 20 pages or so if I remember correctly.

The meta keywords tag is an html tag that was meant as a place where you would use words and phrases to describe your page and help things like search engines understand what a web page is about. You would use some of the the words and phrases you found during research here. Unfortunately it's a very easy tag to spam. People used it to stuff keyword after keyword in the tag, mostly words that had nothing to do with the page. It reached a point years ago where it became pointless for search engines to spend any time looking over the words in the meta keywords tag so now they don't. They read the words in the tag, but more as an aid to help identify spammers. Nothing you do with that tag will improve where you pages rank. Most SEOs ignore it. I haven't included one on a site in years and have no plans to ever include it again.