Before downloading any other games, try the short free experiences/demos from Oculus, "Oculus First Steps" and "First Contact." They'll give you a quick primer for how you can use the Touch controllers to interact with virtual objects, and for how you can move around in a virtual environment (like, you can lean/bend forward to look at something on a table, you can get down on your knees or crouch down to look under a table or duck behind something, you can lean around corners, like you can actually move around in physical space).

Those two demos are "stationary," like you're standing up and you can move around, but you're not walking anywhere. There are games that are "room scale," where you're literally using your own feet to physically walking around in the virtual environment. Start with the stationary demos, and maybe a stationary game like Walkabout Mini Golf. You might have seen videos of people letting their friends/family try out VR, and they'll put their friends/family into something "room scale" when they've never used VR before, and that's how people end up running into a wall or punching an expensive TV. Don't punch your TV or your computer, get used to being in VR before you start walking around. Never run, you'll run into a wall.

Don't set up your playspace with like a chair or wires or like a houseplant or like any sort of object in the area you're playing in; when you put on the headset, the cameras will show you the real world and you'll use the controller to draw an outline of the space you're going to play in, don't have objects you can trip over or step on within the area you outline. Never run, but don't be hesitant about freely walking around, when you get close to the boundary of the outline your drew, a walled outline will show up, and if you stick your head through that wall the cameras will show you the real world. Don't draw your boundary outline directly along the edges of your wall or too close to a TV or monitor, give yourself a little bit of wiggle room, like at least a foot.

Have you ever used a magnifying glass to burn something? Don't expose the lenses to direct sunlight, that can put a burn mark on your screen and you'll have to pay to have it fixed. Not just outside, but like an open window with direct sunlight can do it if the lenses are facing the window. You can purchase plenty of accessories - more comfortable headstraps, slip-on covers for the controllers with a strap that goes over the back of your hand so you can let go of the controllers and they'll stay in your hands like the Valve Index controllers do, a cover for the lenses to protect from sunlight and dust, a more comfortable replacement for the foam part that touches your face - but you don't need to purchase a cover for the lenses, you can just use a fresh clean sock and that'll protect from sunlight damage.

Be wary of plugging in any random charging cable, use the cable that comes with the headset, some people have had an experience where the charging port on the headset melted and that's probably because they plugged in a cable that, like, something something watts or amps or something. If you want a longer cable so you can plug the headset into your computer and take advantage of the Oculus Link feature, do some research before deciding to buy a random cable instead of buying the cable directly from Oculus. But that's not special to VR, cheap laptop chargers you can buy on Amazon set people's laptops on fire all the time, it's never the best idea to buy a random cable instead of an official cable for anything, not just for VR.