While the HUB is vital in Satisfactory, you will need an Equipment Workshop to make a lot of the things that the HUB will give you access to. It can be a little confusing when it is time to build the Equipment Workshop, but in this guide, we will show you what to do, and this will apply every time you open up access to a new building.
After you upgrade the HUB for the first time, you will have access to the Equipment Workshop, but you will need to build it. Hit Q to open up your Builder options, then click on the production Tab.
Click on Equipment Workshop, and you will see that you need 5 Iron Plates and 5 Iron Rods. Both of these can be made by farming Iron Ore from a nearby vein (hit V to use the scanner to find one), and then using the Crafting Bench to turn Iron Ore into Ingots, and the Ingots into Rods and Plates.
To make the Rods and Plates, go to the Crafting Bench at the HUB and pick each item from the list on the left, then hold the Craft button at the center until you have the required amount of each item.
When you have all the resources you need, hit the Q button again, select the Equipment Workshop, and then be able to place it in the world. If the site is unsuitable, the hologram will stay red, turning blue when you find a suitable plot to build it on. Place the Workshop, and it will automatically build on that location.
This is how you will construct the different buildings that you will get access to during the game, not just the Equipment Workshop.