MM:
If, indeed, you only have a few items to be built, get out a pencil and paper. However simple and intuitive the various CAD programs may claim to be, the truth is that there is a substantial learning curve involved with any of them which require considerable time and patience before any degree of proficiency is attained. Especially if familiarity with coordinate systems and geometrical descriptions is not already in your tool bag.
If you are willing to put in the time in order to gain the needed skills, and see this as a lead-in for further or more sophisticated endeavors, fine. In that case I would suggest that a better approach is to start with a commercially available and supported program. These would have most of the bugs worked out and have “Help” features, printed documentation, user groups, examples, training exercises, file compatibility and interchange, etc. An amazing amount of capability can be had for $50 - $100, including 3D. You might want to checkout imsidesign.com among others.