The plan linked above from Fine Woodworking is very good. I helped my brother make a table from this plan. In his case he wanted a glass centre leaf (for reasons that I never quite understood) and her fabricated the slider mechanism himself from stainless steel (he has access to suitable machinery at work). I cut all the joints and made the top and he did all the sanding. We also enlarged the leg size compared with the plan, for aesthetic reasons. We made it out of oak as we have literally a shed load of the stuff in our barn. It is not a difficult project. Good luck with it.