Keyboard Maestro and Excel

Hi all,
I am a complete rookie on KM but an experienced user of a lot of other applications.
I am looking for a video or demo or anything that can explain to me how I can take an excel sheet with app 1000 rows and 2 columns where I can use the first column as url, then click on an image and provide the content from 2nd column into an area. Finally click send. Then loop until end-of-rows.

Any proposals for videos? Descriptions? Related courses? Anything that can help me?

Click "Send" in what? It sounds like there's another application involved (Excel's "Send Workbook" and "Send PDF" act on the whole sheet/book, AFAIK).

Correct.
The url is to get to my single group members on Facebook, the image is the Message-icon and then after having pasted the content, Send the message

And you're sending 1,000 messages? Glad I'm not on FaceBook!

The KM manual and Wiki.

But first you need to make a plan. Do the operation manually, for one row of the spreadsheet, and note down everything you do. For example:

Make Excel spreadsheet active
Select cell A1
Copy
Open the copied URL in Safari
Make Excel spreadsheet active
Select cell B1
Copy
Switch to the frontmost page in Safari (that you opened earlier)
Click on an image
Paste
Click "Send" button

That seems long-winded (and we're about to throw half of it away!) but it makes what you want to do explicit.

If you Copy two columns in Excel then one thing on the Clipboard will be lines of tab-delimited text:

A1<tab>B1
A2<tab>B2
A3<tab>B3
...

..and KM has a "For Each" action that will loop through lines of text on the Clipboard or in a KM variable and do something to each line.

You can use "Custom Array Delimiters" to get the text before or after the tab for each line in your loop, using %Variable%Local_variableName[1]\t% for "before" and %Variable%Local_variableName[2]\t% for "after".

There's a "Click or Move Mouse" that can detect and click on an image, or you might be able to use the "Click Browser Link" or "Press a Button" actions. And there are "Copy" and "Paste" actions.

Putting that all together (and assuming your spreadsheet only contains those two columns):

Open the spreadsheet in Excel
Select All
Copy
Activate Safari
Set variable Local_theText to the System Clipboard
For Each line Local_line in the variable Local_theText
   Open URL %Variable%Local_line[1]\t%
   Click on the image
   Paste %Variable%Local_line[2]\t%
   Click on "Send"
End of For Each

You'll probably have to add "Pause Until" actions between various steps to stop the macro racing ahead of your web browser.

The specifics will very much depend on your setup, the browser you are using, what you actually want to do, and so on. But the above (along with the linked documentation) should be enough to get you started, so give it a go and see how you get on.