How can a technical noob know when it's the RAM and when it's the processor? I can't alt-tab and check the task manager, right?
You can, since this game doesn't have any mechanism to detect when it's minimized and lower resource usage.
You can also set it to borderless window to make alt-tabbing faster.
If you see it running slowly, alt-tab out, and task manager says your CPU is maxed out, then your problem is the CPU.
If it says it's only like 60% then it's not the CPU.
Pretty simple.
RAM/disk is a little harder. If task manager says your RAM is full, that's an obvious hint. Make sure to check with everything else closed because programs like Chrome can eat a lot of RAM.
If you want to really know for sure what's going on, you can use Performance Monitor, a Windows tool, get it here if it's not already installed:
https://docs.microsoft.com/en-us/sysinternals/downloads/procmon
Right click the graph --> add counters --> add stuff to look at, most importantly page reads/sec (scale to 1.0) and disk read bytes/sec (scale to 0.000001 ie megabytes)
Both those measures should be low during gameplay (reads below 100-200/sec, bytes below 25-50mb/sec) and only spike during loading screens or rarely at random. If they're consistently too high or spiking too often then you know for sure the game needs more RAM than you have.
Anyway that's probably more complicated than you want, the simple rule is that this game does best with 16 gb of RAM right now.
Another rule: the less RAM you have, the more important your disk is. With 32 gb of RAM, disk usage is very low. With 8 gb it will be fairly high.