The MCC is used to manage multiple AdWords accounts quickly and easily and also to generate multiple and advanced reports. MCCs are not mandatory but they are set only in case there are multiple accounts to be managed simultaneously.
At the top level there are accounts which contain campaigns and are associated with a unique email address, password, and billing information.
Inside accounts there are campaigns. At a campaign level: budget, location and language settings are specified. The maximum number of campaigns possible is 10,000.
Ad Groups are groups of keywords which share the same ads. Therefore, keywords inside each ad group should be very similar. The maximum number of Ad Groups per campaign is 20,000.
They are created at Ad Group level. The maximum number of keywords per account is 5 million while the max. number of ads is 4 million.
There are 4 main tabs in each account. Other settings such as billing and account information can be found under the gear dropdown menu.
This is an overall picture of the account and a summary of general KPIs.
This is the main tab. Here all campaigns, ad groups, keywords and ads can be managed, edited, created or deleted. In the graphs at the top of the page performance is shown.
In this tab you can find keyword, bidding and budget ideas to improve campaigns.
Here, a set of more advanced tools to improve the performance of the account can be found. Among the most important tools are the keyword tool and keyword planner to develop the portfolio of keywords and the ad preview and diagnosis tool to understand whether ads are shown and why.