On a basic level hubs and switches are the same thing.
On a small network hubs and switches can be used interchangably, the very slight performance difference between them is not noticed.
In my house I use both a router and a hub.
You use a router to "share" your internet connection between more than one PC or laptop.
My broadband connection comes into my house and goes into a router. The router can accept 4 wired connections from PCs (it is also wi fi enabled).
Next to the router is a PC and an ethernet wire goes from the PC into the router to allow it to use the internet.
I also have an office upstairs so another ethernet wire goes from the router through the floorboards into my office.
I want to use 2 computers in my office, so the ethernet wire from downstairs plugs into a hub in my office.
Then the two computers in my office both plug into the hub with an ethernet wire each.
So the two PCs in my office "share" the hub, and the hub and the PC downstrairs "share" the router.
Hopefully showing how they are used in a practical sense makes it clear.