Honestly, if you choose the right bench, a two-person install is very doable. Most commercial street benches with a modular or leg-plate design are made for exactly this kind of setup. You won’t need a crew, a crane, or special skills. What you do need is a clear flat area, basic tools, and about 30 to 60 minutes.
The real difficulty comes down to weight and alignment. A lightweight aluminum or steel slat bench usually weighs between 60 and 120 pounds. That is manageable for two adults. One person can hold the bench frame steady while the other lines up the legs with the anchors or surface-mount plates. For surface mounting on concrete, use a hammer drill, masonry bit, wedge anchors, and a socket wrench. Mark the holes through the base plates first, then move the bench, drill, set the anchors, and bolt it down. For in-ground installation, dig two post holes about 18 to 24 inches deep, set the legs, check level, and fill with quick-set concrete. That is still a two-person job, but it takes longer and requires more patience.
The main challenge is not strength—it’s keeping everything level and square. If the ground slopes, use shims or adjustable feet. A small magnetic level and a rubber mallet help a lot. Also, keep the bench packaging on until you are near the install spot so you can slide it safely.
So to answer your question directly: assembly is easy, installation is moderate. If you are bolting to an existing concrete pad, expect about 45 minutes with two people. If you are pouring concrete footings, allow two to three hours including curing setup time. Pick a bench with pre-drilled mounting plates and a two-piece or modular design, and two people can absolutely handle the whole job without hiring a contractor.