Right way to develop a simple configurator

This is my scenario: i want develop a furniture configurator based on “click to add model” mode; user simple clic on icon, then choice an object from catalogue; then user can add others objects by clicking on icons over previous object (up, down, left, right).
The flow is left > right, bottom > up, so the first object should be added to bottom-left corner.
User can choice room dimensions, so i don’t know the plan dimensions.
My models can have different dimensions and origin in center or in a corner.
What is in you opinion the right way to write this?
Any comments and suggestion will be appreciated, thanks