are "symbols" or "block symbols" sorta like "personal IP" ???

Tricky is right, please look into Verilog or VHDL. (I learned schematic first, then VHDL, but now prefer Verilog. Either will work fine for you, but I find Verilog easier, especially at first. ) Your design will have hierarchy, which is done through module instantiation. Google should show examples, but almost any HDL design has hierarchy. The hierarchy browser in Quartus can be used to open upper/lower files quickly. You'll also want to use the RTL viewer, especially at first, to "see" what you write looks like in schematic.

FYI, I find having a schematic background to be very useful, as I still write code that I think of in schematic terms first, for the most part. I find designers often get in trouble early on when they have a software background and try to write HDL like software. You'll have a bit of a learning curve but it will be worth it in the end.