Hires, interlaced screen on Amiga Devpac, with window, menu and buttons

Using DevPac 3, I need to produce an application that displays graphics in a similar way to DPaint. No right-hand toolbar, just a vertically scrolling image, preferably in HAM mode.

Application digest:

• Open a new hires interlaced screen in as many colours as hardware will allow
• Basic menu structure that I can manipulate (Top Right-click menu)
• A project window, similar to the DevPac editor

• A control panel along the top similar to the one in Digita Wordworth with text boxes, buttons and tabs

• I also need an off screen buffer that is as wide as the screen and as tall as memory will allow.

This needs to be compatible with:

• Workbench 3.0 and above
• 68020 and above
• ECS & AGA chipset
• 0.5..2Mb chipmem + 0..∞ fastmem

I don't know where to begin, and any help will be gratefully received.

This guide may give you a few hint specially about "intuition" programming : http://gulasoft.uw.hu/AmigaDoc/AmigaAsmTutorial.txt

You can also find exhaustive documentation about kernel libraries here : http://amigadev.elowar.com/read/ADCD_2.1/

I hope it helps