What do you think is out of your skill set? There are lots of people here who do crazy things with custom apps, custom drivers, and complicated rules, but you don't need to do any of that: Hubitat has built-in drivers for nearly any common type of Z-Wave or Zigbee (technically ZHA) device with a few LAN and cloud integrations, so if you stick to those you won't need custom drivers. Hubitat also has lots of built-in apps, which are basically "templates" you can use to easily create automations for common tasks (e.g., turning lights on with motion, notifying you when a contact sensor opens or closes, etc.).
If you're totally new to home automation, you can probably learn most of what you need to know from the Hubitat documentation, which is also where you'll find the list of supported devices. (To be honest, the SmartThings documentation isn't bad either and Hubitat was very much inspired by that platform, but anything you see about how to use the app will be different since on Hubitat that is mostly done from the web admin interface--and SmartThings has been going in weird directions lately with lots of Wi-Fi devices and a "new" app/device model.)
You'll likely also want to familiarize yourself with the two main protocols Hubitat uses, Z-Wave and Zigbee, but the main takeway is that they are mesh networks where mains-powered devices are generally "repeaters" that help extend your range (usually not an issue yet if you're just starting out, only have a few devices, and everything is relatively close to the hub). I'd recommend avoiding cheap, Wi-Fi "IoT" devices that generally don't have local or documented interfaces to be usable with a system like Hubitat (again, the supported device list will help here).
From a technical standpoint, you'll likely also want to assign your hub a "static" (reserved DHCP or however your router does it) IP address, and you'll probably also want to do the same for other local devices Hubitat might connect to (Hue Bridge, Lutron bridge or repeater, or whatever else you may have). In many cases this is optional, but in nearly every case it is far less likely to cause problems if you do.
If you think you can handle that much, there are lots of people here who would be willing to help if you have questions getting started with Hubitat, like how to pair/add devices (nearly every device has an instruction booklet that says how to put it into pairing mode or reset it, and it's easy to put Hubitat into "discovery mode" to find them) or how to set up automations to make them do things you want (you already know these are called "apps" on Hubitat, and many are available out-of-box for common tasks).