Smart Guides are turned on automatically. Clicking and dragging an object will reveal Smart Guides when the object aligns with other things on the slide.
Click and drag an object until alignment guides appear.
If the other alignment options don’t work for your needs, freely move objects using the arrow keys on the keyboard. This option is particularly helpful if you just need to move the object a short distance.
Select the object(s) you want to move.
Tap the arrow keys on the keyboard to nudge the objects to the desired position.