well folks im just sitting here looking at my newly built cnc machine from hobby cnc  and let me tell you it has been a journey.
it is all wired up ready to go, tuned the motors and changed all limit and homing swithches to sheilded cable.

all directions are correct and all is ready, and i have been waiting for this point.

i have downloaded mach3 for test use and to see if it is for me.
it looks good and seems to be user friendly.
i have read it from front to back and i am ready to go.
now im looking at it and saying what is next.

how do i begin to cut parts,what is the correct wy to go about this,

1. mach3 seems to be good , what about turbocad , i knowthat it runs in the dos mode , that im not worried about, im sure it ia a matter of choice.

2. knowing what these programs do what is the next step in the proceedure or software , that i will need to move closer to testing 

thanks.......Robert

Buying or building a cutting tool is only the start of many years of spending sometimes substantial amount of cash.

From my experience the best way to learn anything is to have a project,  that way you can focus on getting one thing right at a time. Set yourself a task, maybe you are into clocks, loco's, boats, aircraft, what ever.  I think its time to decide what you are going to make on the machine, then gear yourself up to achieve this goal.

Think about it this way :-

What am I going to make?

What materials will I be cutting?

What tools will I need?

Do I need 2D, or 3D code generation?

How am I going to hold the work pieces?

Do I need special measuring tools?

Once you know the answers to these questions, the next list of questions will be automatic and a path will develop

At the end of the day the G-code part is the last bit you need to worry about, and we can help you with that bit too.

Graham.