Yay! \o/
Ok, you're excited. That's ok, we're excited too
Let's make the most of your system.
First - unplug it, and get any model numbers, chassis numbers, tube types from any stickers or such on the back and inside (it's ok to pop the back off if it's unplugged for more than 5 minutes - you won't get a shock). Take pictures and post them. The more the merrier. That way, we can ID your unit, and the various parts.
Second - what's the condition? Has it always been used? Was it sitting for years? Does it hum? Does it act weird? Most importantly - has it been overhauled or repaired? That last one is important - for long term safety and reliability, you need to replace some parts that wear out. Also, there are parts that can fail and take out expensive and hard to replace stuff. That needs to be checked out, too.
Third - that phono unit might need a cleaning and lubrication. Not a hard job.
You might have to put a bit of work into this thing to get it 100%. But, the service information for this unit is almost certainly available! And, many parts are, too.
What's your skill level? Can you use a multimeter? Can you solder? Can you use basic tools?
The turntable should turn in every speed with a good amount of power. If it slows during the change cycle, or stops, that needs to be fixed (and it can be). The needle on your looks to e a ceramic type, with a flip stylus. On these, you have a lever that flips between 33 and 45 speed records, and 78 speed records. Just flip it so the right setting is showing when you look down. It might say 'LP' for one side and '78' on the other. Use the 'LP' setting.
It looks like yours is able to safely play stereo records, though these units weren't the best for records (they're ok, though). But, you want a new needle and checking everything out before you put anything beyond a scratched up test record there.