please I need a brief description on how to go about it Thanks guys.

MrNigeria.:
please I need a brief description on how to go about it Thanks guys.

Method 1:
Select the layer with the object you wish to add the border,then go to Edit>Stroke and then set the stroke to outside and size to 1px

Method 2:
Select the layer and click on the FX button, then go down and tick the stroke option, type 1 in the stroke size option and click ok.

MrNigeria.:
please I need a brief description on how to go about it Thanks guys.

OR (since I guess its for the ad competition and you are using photoshop)
Select all layers via the layers panel
Group them together (ctrl+g to the rescue).
Notice they are now a single layer
Stamp visible (ctrl+alt+E).
Notice we have two layers now
Turn off the visibility for the bottom layer
This is done by clicking on the eye icon beside the layer (on the layer panel)
Select top layer, right click, select blending options
Check Stroke, set to 1px, inside and be sure to use a dark colour (black, to be on the safe side)

Good luck!

Forget the long epistles, I had to lay it as simple as I can