DE0-Nano SoC Kit - Questions about Qsys and automatic tcl pin assignments

Hello, I'm writing here after a two-days research on internet, without successful answer to my question(s).

I'm facing problems with the part of the HPS-FPGA tutorial included in the CD for DE0-nano platform that explains how to automatically assign pins, and I found the identical problem following this (https://zhehaomao.com/blog/fpga/2013/12/27/sockit-3.html) guide.

I'm running Quartus 15.1 Prime Edition on both Ubuntu 14.04.3 LTS (ok, I know it isn't supported) and Windows (that is supported instead, so my question should be valid).

Here's the problem:

when Qsys project is generated, and included in Quartus project, I throw an analysis and synthesis task. Then I should execute the TCL script for pin assignment... BUT: after the execution, I see no variations in the assignment table and also in the pin planner window. On Ubuntu I also get some errors during the execution of the script, although the Quartus software and all the Altera Suite work smoothly on this system.

Here's the question:

what exactly the TCL pin assignment script does? should I see changes in the pin assignments or not?

extra: does the Qsys system need to be toplevel in my Quartus project?