Basic questions regarding NIOS

Although there are "getting started" tutorials on how to setup NIOS, e.g. this, there are some basic questions that I didn't find the answers for them.

1- DE0 has no LCD but it has VGA connector. So, when I write a hello world program, what should I do to see the message? Will that display the message on the Quartus window?

2- It seems that NIOS is accessed with C codes. So the question is how can I pass my VHDL code to the NIOS? For example, I have implemented a Booth multiplication algorithm via VHDL. Now, I want to send two numbers with NIOS (the C code) and perform the multiplication with the VHDL code and then display the result (again prinft on NIOS side).

Maybe these are simple questions but I didn't find a clear methodology for that. Surely there exists tutorials and manuals for that, but I have missed that.

1. You will need a VGA driver of some sort, written in HDL (probably some out there if you google search). Usually these will be a memory buffer of some kind, that you could write over from the NIOS. You'll need some sort of text-> memory driver though, as the memory will be addressed at a pixel level, not character level.
2. NIOS is a processor, VHDL is a hardware description, not a program. SO you would need to attach your custom HDL via an Avalon interface so that it can be accessed via the NIOS.

NIOS is just a processor, ie. another IP block that would be be connected in your HDL. QSYS can be used to wire them all up.

So, you mean there are additional steps after reading this Altera tutorial to make it fully practical??
Can you explain what keyword should I search for further steps?

That tutorial uses an already existing Nios System.
What you need to do is generate the NIOS system in QSYS. You may want to go through this tutorial: https://www.altera.com/support/supp...amples/design-software/qsys/exm-qsys-tut.html

It sees that I am in an infinite loop!!
The DE0 CD package has some demonstrations for the peripherals. For example, there is a fodler for SD card (page 44). There, I see lots of files and I don't know the steps to follow. It roughly says to run the batch files and all things will be OK.

So, if I want to read some data from an SD card, do I have to work with Qsys and define the components (reset signals, PLL, RAM, ...) by myself, or I have to stick with the demonstration folder for SD? As another example, should I do some works(!) if I want to read foo.txt or bar.dat?!

Or I have to first warmup with Qsys and design some simple unit before using the SD card project files?