Need code for Nested loops and creating graphics without paint

[A6Packof2Cans]

Here's what I need:

1. How can I create a graphic (A fish for example) using a method other than paint?
2. I need to draw a very simple castle, it can be in paint
3.How would I use nested loops to make the fish move horizontally across the screen? I need a button to make the loop start, how can this all be achieved?

Thanks in advance, it's probably very rudimentary to most of you here, but I'm having trouble getting started on how its all done correctly.