Like a lot of people I started out with no experience, no real idea of what I was doing. We just accepted that we didn't really know what we were doing and forged ahead anyway. Nowadays there's a lot of "How to DM" advice out there, you can watch some videos and so on, but really the only way to learn and get into the game is to do it. If you have character sheets, something to write on and others willing to play, you have what you need.
I'd probably recommend one of he starter sets or search for blogs/streams that talk about running your first game. I ran Lost Mines of Phandalver back when it came out, we had fun. Best news is that you can get it for free on DndBeyond (more on that below). Of course there are a ton of live streams as well just don't expect anything like what you see online because no one expects professional voice acting, at least not for long and it's not why we play anyway.
For physical? I personally prefer minis, but that's because I enjoy painting and they work better for me than theater of the mind since I'm a visual person. You can start with scraps of paper with numbers on them or anything else you have handy. If you have access to a printer you can find all sort of images out there, I still occasionally just print out monster icons because either they're something weird or I don't have a mini big enough. I just had a game where I had a couple different kinds of oozes that I printed out. Game stores also sell minis and you can buy plastic minis online. One thing I did was bought a bag of plastic zombies - you just need a way to keep track of which is which. For that I just slap a little paint on them so one is red, one is blue, another is red and blue and so on. They don't have to be pretty, they just have to be distinct.
DndBeyond.com is an online tool, the core basic rules are supported for free and it has a character builder for your players. In order to get all the rules from the PHB and MM you need to subscribe and buy the books but it's fully functional without that. As I said they have LMoP online and you don't even have to sign in to get it. It's a good start to understanding how to build a character and is a handy reference, even if it isn't worth paying for a thing.
Other than that it's just jump in and learn as you go. If you need more help just let us know!
