Bid on keywords - how?

In Google Ads, a search campaign. Start with phrase and exact match only, broad match will spend your budget on loosely related stuff while you're still learning. Add negatives from day one (free, jobs, how to, whatever doesn't fit) and check the search terms report every few days to add more. Keyword Planner shows a top of page bid range for each keyword, which is a decent starting point. Keep the daily budget small until you know which terms convert.