The third way: change to [BLOCK] select mode by pressing Ctrl+Shift+B. Then make a vertical selection spanning multiple lines at the beginning of the lines you wish to indent (quick way to do it is Home, and then Shift+↓ multiple times, or you can use the mouse) and press Space .
Also, in the settings, you can change how many spaces a tab will indent. For most programming languages, I keep it at two, instead of the default four.
The fourth way: Kate will automatically indent blocks for most programming languages. Normally, you want to indent a block when you’ve added an encompassing outer block. You can do this by simply cutting and pasting the entire outside block. All inner blocks will then automatically indent properly upon pasting (assuming this option is enabled: “Adjust indentation of code pasted from the clipboard”).
I was just selecting several lines the same as one would for a copy - paste. Just left click and drag. I guess that means nothing to Kate. But by using the magic keys what you highlight tells Kate this is more than just highlighted text, it is a block meant for Kate’s use.