Your ad has launched and is delivering impressions evenly for the duration of the campaign. Reddit users see your ad above the #1 post at the top of your targeted pages and on the frontpage for logged-in users subscribed to the targeted pages.
To view your live ad, navigate to your advertising homepage and click the "edit" link under the ad's title. This will take you to the ad's campaign dashboard. On your dashboard, you'll see the targets for your ad. When your ad is live, a blue "view live" button will appear next to each individual target. Click this button to see what your ad looks like live on the targeted subreddit or Reddit page. This doesn't count as an impression.
This is your internal view of the live ad:
Public view of your ad:
Because ads are rotating units based on cost-per-thousand impressions (CPM), you won't see your ad with every single pageview.
You can see all ads that are running in a subreddit by going to the subreddits 'promoted' tab. On any subreddit, click the "promoted" tab at the top or append /ads to the end of any subreddit url (e.g. reddit.com/r/askreddit/ads).