Page borders? I'm not sure what you're asking but you ca use the Rectangle Tool in the Tool Bar on the left to Add a Rectangle around the page.
You can apply a stroke colour by going to Colour Panel and selecting the Proxy for the stroke and the colour you need.
And you increase the Stroke Width by going to the Stroke Panel.
Like a page border?
Making a kids book so doesn't need to be professional.
Most likely you are going to want to create your page border as an illustration of some sort and place it on your master page as imported art. Don't forget to make it oversize for the bleed.
I've found this topic to be helpful to something i'm working on: a quarter page advertisement. I wanted to create a border around my advertisement, filled with a gradient, and was able to accomplish this, but is it possible to give the inner border of the gradient a solid black line? Or do i need to create another rectangle to do this?
Thanks so much,
This is not intuitive, but you can make a custom stroke style of type "stripe" and set the proportion of gap and stroke to anything you want. You can then apply the style to your stroke and apply the gradient swatch to strok and balck to gap, or vice versa, depending on relative sizes and which is inside or outside.