PC Hardware: Decide budget. That determines everything. PCs are lego with a power supply. If you don’t want to or don’t know how to build it, expect to spend more. External sound thing only matters if recording external sound sources cos of DA converters and the build quality of the device, otherwise onboard audio is fine. If recording external sound sources and you don’t know what you’re doing, don’t worry hard about the best of the best of the best first time out as you will get so many other things wrong this is not the biggest thing to care about, you can upgrade down the line and just go with the built in audio card, whether its motherboard or a PCI card. Seriously worry about this later when you’ve done more. Also, it spreads the cost and by then you may have decided this isn’t for you.
Software: Win10, apply updates. If going Mac, lol for even asking on here, just do what Apple tell you.
DAW: Whatever floats your boat but this is the most important software decison of all. There are demo versions of everything, find something that allows you to create a workflow how your mind works. You’ll see people endlessly arguing over details. Ignore that shit. If it works for you, it works. End of. Take pressure to this or that with a Siberian salt mine. You may change later. That’s fine too. By the time you change you’ll be making a more informed decision based on your own experience.
Hardware connectivity: Worry later. Early days all that matters is figuring how all this stuff goes togther. Learning how sound works and mixing is the biggest part of it all other than generating music itself. If you care about hardware, look at the hardware thread but good luck reading all of that before the sun goes dark. This takes us back to budget. Nothing wrong with buying some hardware devices but bear in mind you’ll spend a lot of time figuring out how to make it all go together before you get to the same starting position that software will have got you to long before that. It can be rewarding but don’t fool yourself that its automatically better. You said starter, so I’m going with that.
Music input: Decide if you wanna press pad buttons or play keys. Then go accordingly. Doesn’t matter which works better for you, if it works better for you then you made the right choice.
If going the VST route, try some free or demo VSTs before spending money.
Demo stuff but stay legal cos Malware is a cnut.
I may have missed something. Its been a long day.