My first pc

Step one, inspect for damage inside and out. Also, as you remove the internal foam packing that is holding everything is place give the GPU, RAM and any other PCI boards a little push to make sure they're still seated properly. (Make VERY certain that you're grounded while touching things inside the case. touch the metal case before touching anything inside.)

Then, when you turn it on it's really tempting to start surfing the web etc just to see what you're getting as far as performance... this is not a good idea. Anti-virus first. Whether its Windows Defender or some other 3rd party software you have to protect yourself and your new toy.

Then I would suggest installing programs you are going to need to keep the machine clean and clear of malware. Things like CCleaner, MalwareBytes, etc.

Once you've made certain that you are protected head on out into the wide world of PCs and see what's what.

I'm sure others will chime in with more and better solutions. Those are the steps I would take.

Good luck and welcome to DS!

Snaike may not realize Windows Security is active by default to protect you from viruses. I've been using it over a decade, and it has been sufficient to keep me safe. It's all I use now.

It is a good idea to install an anti-malware specialist like Malwarebytes he mentioned. You'll find a still-useful list of "Must Have Software" in "Computer Related" > "Software Discussion" here on the Forum. If you like what you read about Malwarebytes, download the free version and check it out. If you pay for it, it works on autopilot in the background. If not, it still protects your system but you have to tell it to scan your system every couple of weeks. That's not something you want to forget about. Windows Security works automatically in the background 24/7, but is more for anti-virus.

Hope it helps.