Following on from Somarls point; the 'Hands On' book provides helpful tips for such projects.
There isn't a single right answer to your question; there are different ways to acheive what you want that will more easily spring to mind once you get more experience.
What I would do is make a decision whether to learn how to model, or avoid editor based modelling altogether in order to focus on the code. It is down to you to decide whether you like modelling or not; you do not need to use a 3D modelling program to produce your idea.
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To hard code everything, look into memorizing the available commands in the Basic3D and GameFX sections in the help documentation.
In the Basic3D section you find that you can create the board out of a box or plane, which can be textured with the design of the board.
The Marbles can be created using the [Make Object Sphere] command, and the dimples in the board can be coded using the [PERFORM CSG DIFFERENCE] command in the GameFX section; this uses one object to carve out another using its polygon form. If you do not wish to carve out the dimples, normal mapping can be used to create the dimple effect with textures. Normal mapping is acheived using FX shaders, check out
Dark Shader if interested.
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To use 3D modelling, I would use
Blender. Usually Blender is not easy for people to learn when you have already gotten used to using other 3D modelling programs, the work flow in Blender differs. It takes time to learn, but after you learn it you can create anything you want, now and in the future.
The game board can be acheived in Blender by pressing shift A, selecting cube. Then shift A to create a sphere. You resize them pressing S and resizing the spheres. Finally you add a boolean modifier which can use the spheres to create the dimples in the board.
On my website there is a guide for
exporting Blender files for DBPRO, aswell as other
DBPRO guides and tutorials.