Here is how you do format that you are looking for.
To make it into a power of a number
Press Ctrl+Shift+P to make the text superscript,
Type your base number, then press the above keys, type in your power number, spacbar, above keys again to get back into normal size again.
If you want to lower the number as a footnote, then you follow the same example follow the keys below
Ctrl+Shift+B to make the text subscript.
You can set the size the superscript and subscript by going to Format in the toolbar, then selecting character, then clicking on the position tab.
Hope that will be useful to you.