You now have a grid to select a position for your textbox on the scene. Here's how you can change position.
On the storyboard, when you click on the textbox, a menu to edit text. In this menu, you will see a Grid icon which will show you the text positions to select from.
You get 9 positions to select from. Refer to the screenshot below:
Please note, your text will be aligned as per the position that you select. If you select any 3 positions from the left side of the grid, the text will be left aligned and so on.
In addition to these 9 positions, you can also drag and move the textbox to the position of your choice.