1-Once you have accessed the main page, your AdMob account shows a resume of the statistics. 

2-Reports available include the following metrics:

• Network requests: The number of times your app requests to show an ad.
• Impressions: The number of times ads are shown on your app.
• Fill rate: The number of times ads are shown on your app, divided by the number of times your app requests to show an ad (e.g. 100 impressions / 1,000 requests = 10% fill rate)
• Clicks: The total number of times ads shown on your app are clicked by users.
• CTR (click-through rate): The number of times ads on your app are clicked on divided by the number of times ads are shown on your app. Example: 10 clicks/ 1,000 impressions = 1% CTR
• Revenue: The amount of money you earn from your apps
• eCPM: Effective cost-per-thousand impressions is an indication of developer or publisher earnings per one thousand ad impressions. eCPM is calculated as (revenue / impressions) x 1000. (e.g. $10 revenue / 10,000 impressions, your eCPM is $1).

3-You can view data relevant to one App, all Apps, or just for a certain block of Ads.