Google Adwords Interface Tabs Explanation
Opportunities Tab
It provides suggestion to improve your campaigns performance. As per your account performance history, settings & google search volume & trends this tab create the opportunities to improve your performance.
For more info: https://support.google.com/adwords/answer/3448398?hl=en


Report Tab 
As its clear by name i.e reports. We can understand what this section is about. In this section, we can see, organize, and analyze all of our campaign performance with advanced tables and charts as well as handy ready-made reports.
For more Info: https://support.google.com/adwords/answer/6201327?hl=en


Tool Tab
This tab is combination of various Adwords tools to do multi useful activity for your campaigns. Like – see account changes, setting up conversion, finding keywords & previewing your ads etc.
For more info: https://support.google.com/adwords/answer/1722070?hl=en

Campaign Tab
In campaign tab you set up all your campaigns & manage. Like:
•    You can change the settings of your ad groups, ads, and keywords. 
•    You can change the budget and status of campaign with one click. 
•    You can also see and customize your account statistics, download your data, and more.

Ad groups Tab
The Ad groups tab is a fast way to see and edit details of all the ad groups in your AdWords account. This tab can show you ad groups from a single campaign or from all campaigns.


Settings Tab
The Settings tab lets you adjust settings that affect an entire campaign, such as budget, network and bidding options, language, location and device targeting, campaign end date, ad scheduling, and more.


Ads tab 
It is where you can view data about each individual ad in your account. This allows you to compare ads, see which ones are most successful, and use that information to create even better ads. You can also edit, pause, or remove ads that aren't performing as well as others.


Keywords Tab
In this tab you can see keywords that you've selected for all of your campaigns, or just those for a single ad group. 
You can also get performance and quality information about your keywords that can help you decide whether to create more keywords, or edit, pause, or remove the ones you've already created.


Dimensions Tab
The Dimensions tab lets you slice and dice your data by the dimension of your choice across an ad group, a campaign, or your entire account. For example, you can view your total stats by month, hour, or geographic region. 


Display Network Tab 
The Display Network tab is where you can manage your display campaigns and see performance data about your ads on the Display Network. You can manage your display campaigns by adding or editing targeting methods like keywords, placements, topics, interests and remarketing lists, gender, and age. 
In addition, you can see information about how your ad groups perform, use data to optimize, manage bids, and remove low performing targeting methods.


Show Tabs  
The Show tabs button contains other tabs that you can add to your account, including Ad extensions and Auto targets. Just click the boxes next to the ones that interest you.


Date Range Tab
The date range box lets you customize your statistics table on the Campaigns tab to see only the data from particular periods of time. 
The left panel of your AdWords account is full of shortcuts to many types of account information:
•    Click All campaigns for a list of all your campaigns
•    Click individual campaigns or the ad groups beneath them to be taken directly to them
•    Click on the links for Shared library, Reports, Automated rules, and Custom alerts for status information, if you've enabled any of those features to run.

Statistics Table  
The statistics table below your graph shows detailed information about statistics such as clicks, impressions, and clickthrough rates. 

The Toolbar
The toolbar buttons help you quickly find and organize your account information. 
•    Segments split your view of data into separate parts. There are many different segments that you can apply to your data, such as device, click type, and network, and time period
•    Filters search your statistics table for specific information, such as keyword text, bids, and clickthrough rates (CTRs
•    Columns provide a variety of statistics about your account. Choose which ones you'd like to see in your table, then rearrange and save them in the order that you prefer. 
•    The Graph button makes your performance graph visible or invisible and sets your graph display options.
•    The Download button lets you download any view of your statistics table that you've created to create reports in formats like .csv and .pdf. 
•    The Filter search box allows you to quickly filter your statistics table view by campaign name, ad group name, ad text, or keyword text.

please see the video also: https://www.youtube.com/watch?v=NZ6pFkClMCI

For more info : https://support.google.com/adwords/answer/1704365?hl=en
Source Google support