Easiest way is to load the data, ensuring that the twitter "created_at" attribute is formated as:
EEE, d MMM yyyy HH:mm:ss Z
You need to do this in the metadata for the tweets.
You can then use put the created_at date on the group dimension (category axis) and use the count of tweets as the series metric.
The only issue with using the unformatted date is that it retains all of the time component too, which can look a bit unsightly.
If this is an issue for you (as Im sure it will be), then you can use the reformatter control to strip out the different date/time parts into string parts such as month, date (format as YYYYMMDD), hour, etc.
Here is an example:
$out.0.Str_Hour = date2str($in.0.interaction_created_at, "hh");
$out.0.Str_Date = date2str($in.0.interaction_created_at, "yyyy-MM-dd");
$out.0.Str_Year_ = date2str($in.0.interaction_created_at,"yyyy");
$out.0.Str_Month = date2str($in.0.interaction_created_at, "yyyyMM");