Can you post pictures of your tanks overflow as well as your sump and their relative placement together?
It is hard to specifically advise without seeing what we are working with. However, basically, you should get familiar with the three most common types of overflows: Durso, Herbie and Bean Animal.
Then you need to decide what type of piping you want to use. If you are new to this, then flex piping is the easiest to work with, but costs a little more. If you do it right, you won't need to glue anything and you can use all threaded connectors. Another advantage to flex pipes is that they can be designed to minimize (or eliminate) and elbow joints. Otherwise, if you want to learn to use PVC and save a few bucks, look up some Youtube videos on how to work with it.
Once you have decided your plumbing materials, you can then get the appropriate bulkheads and fittings and get to it. Plan on at least one valve for your overflow line(s), but for a more flexible design, put a valve on each of your overflow lines...
If you take a look at my buildthread here:
https://www.reef2reef.com/threads/sbashs-220-gallon-through-wall-build.319549/#post-3975746
You can see my roughed in plumbing starting at that post, then I refine it as the build progresses...
Once we can see what we are working with, we can advise you more specifically...