I can't figure out how to select text. I want to add a stroke.

If you want to adjust the stroke properties of text then you have to use the vector editing facilities, not the text editing facilities.

Use the Select Shapes tool to select the text, then in the Tool Options docker will be the Geometry, Stroke and Fill tabs. Click on the Stroke tab to use the stroke editing facilities.
For the Fill tab, don't try a gradient fill because it will turn solid red because of a bug that has been reported.