Don't forget to refresh you mappings in Kibana. And don't index these new documents in the same index, otherwise the data is going to look very strange. Either delete the index, or create a new one to start writing to (and add that new index pattern to Kibana).
If you want to create a visualization, use a Date Histogram on @timestamp on the X-Axis. If you want to look at a specific set of time intervals, like every hour, adjust the interval to match what you want. Next, add another bucket to split the bars (or lines or area) and use a Terms aggregation on the parameter field to. By default it'll show you the Top 5, but you can adjust this.
Now click the play button at the top.
The first thing you'll notice in the visualization is that you'll have more than 5 (or whatever you set it to) items in the legend. This is by design, as it's showing the Top X for each bucket (@timestamp interval you set, or the one it picked in Auto mode).
If you're just trying to see the top requests for the last hour, for example, set the interval to 1 hour, and set the time range in the timepicker (top right of Kibana) to cover at least the last hour, or the hour you actually care about.