The geometry of a link suspension would take an encyclopedia to properly explain, so here is a condensed version. The four-link uses four separate suspension links to locate the axle fore and aft and side to side while still allowing it to articulate and move up and down over obstacles. This is done with at least two of the links angled for side-to-side axle location, and we have seen every variant of link configuration such that the upper pair, lower pair, or both pairs of links are angled inward. We have also seen the converging ends at both the axle or at a chassis-mounted crossmember. Just remember that if you angle both the upper and lower link pairs, they need to have opposite ends angled inwards. The other job of the link suspension is to push the truck forward as the axle drives over obstacles, and depending on the geometry and lengths of the links and their mounting points, the truck will either do that well or it can jack up or squat the chassis. The links must also be separated vertically at both the axle and frame ends so that they can fight axlewrap. Plus as the 4x4 corners the geometry of the links in relation to the vehicle's center of gravity can determine body roll, which is how much the chassis wants to lean side to side. Many of these issues can also be influenced by sway bars, spring rates, and shock valving, not to mention the ratio of unsprung weight (axles and tires) to sprung weight (chassis, powertrain, and everything above the suspension). If you are considering putting a four-link in the front end of your 4x4, steering will become an issue, unless you go to full hydraulic steering. This is because the steering drag-link geometry is rarely built to follow the same geometry as a four-link and will result in bumpsteer. Another variant of this design uses one giant A-arm style upper link with two parallel frame mounts and a single upper axle mount in conjunction with two lower links. This is what is known as a three-link suspension. A three-link usually works just as well as a four-link of similar design, but the upper A-arm sees higher stress loads as the single joint end.
Link suspensions are a great design for your 4x4, and can result in optimal performance with greater approach and departure angles, freer yet more controlled axle movement, and simpler spring and shock installation, but remember that the vehicle is still supported by the springs whether they be coils, coilover shocks, quarter-elliptic leaves, airbags, or air shocks. These must all be mounted to move in the same arc of movement as the axle, and limiting straps may be necessary to keep the axle from drooping out past the travel of shocks and driveshafts. As with any suspension, all welds, link materials, and brackets need to be up to dealing with the stresses of suspending a heavy-duty 4x4 bouncing over rough terrain. We've seen every link mount imaginable tear off of frames and axles, not to mention the links bending and rod ends peeling open, and when they go they can take expensive shocks with them. Even though trick suspensions can perform amazing acts on the trail, they also need to be built to take the abuse. Those old leaf-sprung Jeeps didn't go that fast, but maybe that's what kept them in one piece.