Okay, I’ve got an HP Pavilion with a Radeon graphics card, but to get to Switchable graphics, I simply right-click on my desktop and “Configure Switchable Graphics” is an option in the context menu.
I’ve set it so that the system asks me each time I open a new piece of software if I want to use “High Performance” (my Radeon) or “Power Saving” (the Intel chipset)
Some games will still only show the Intel Chipset as the only one available in their setup details even if you’ve switched the graphics over (Skyrim and DXHR I’m fucking looking at you!), but they will run things like DX11 and high-level graphics settings regardless. That’s more or less the best way to indicate if you’ve got the correct card selected.
If you’re planning to use your laptop mostly as a tethered rig (only connected to mains power, rarely if ever used off of battery) you can go into the BIOS and force it to only use your Nvidia card at all times. This is a bit of overkill, because you don’t need dedicated graphics just to browse the web, but it’s the better option if you don’t want to have to mess around with settings all the time. I don’t have the details on me, but something like “Lenovo force video card in bios” or similar in a google search should turn up some decent results.
[ETA]: Only dick around in the BIOS if you’re really confident about what you’re doing, or you’ve got someone who’s willing to walk you through it.