How do I align my jpg to a true horizontal and vertical?

[Ravenowl]

I have been working on page for a book. The background is a jpg with text boxes on it.

 

While using my trackpad, zooming in and out, I must accidentily have rotated the image slightly. Now the  text in the added boxes is 'off' as it follows the slanting. I cannot seem to get it straight again. 

 

I have tried various tips about aligning and snapping but either I am getting it wrong or it isn't meant to do what I want it to do.

 

Any help appreciated, particularly if it is in plain English as I am not a tekkie :wacko:  

[Alfred]

When you hover over the rotation paddle at the top of the selected object's bounding box, the cursor changes to a double-headed curved arrow. Click and drag to left or right, holding down the Shift key as you do so; any rotation will be constrained to a multiple of 15°, so it will be easy to make it exactly 0°. Alternatively, go to the Transform panel and set the rotation to 0° by typing in the R box or by adjusting the slider.

[R C-R]

Since you say you use a trackpad, it is possible you have rotated the canvas rather than anything in it with a gesture. If so, selecting View > Reset Rotation on the menu bar will set everything back to normal.

[Ravenowl]

Thank you both very much for your help.

Tried the reset rotation, that seems to be working because you are right, I moved the whole thing rather than an object within.

I also tried the manual adjustment, problem is that its darn difficult to get it exact. So the automatic one seems to do what I am looking for. 

[R C-R]

If you don't want or need to rotate the canvas with a trackpad gesture, you can turn that feature off in Preferences > Tools.