Page Layout

So now I'm getting around, I can fill a dropdown from a stored procedure, get the selected id and call another stored procedure that fills my datagrid!!

I have also tried to click on a row and load values into textbox!!

But now to design, how can I get a nice design, lite more space between to drop down and the row of textboxes and a lite more space between the labels and textboxes, and then i need two buttons left of the textboxes.

I tried rows, bur it didn't work

It is not clear what you have tried based on your screenshots. Did you put columns inside the rows? Did you try setting some margin?

I'm looking for some tutorial that explains how to build i nice UI

You can check the documentation: Working with Pages