how can I look to the TOP module of a design

[Shandongwzl]

Really sorry to ask but my knowledge is really limited.
I am now working on NetFPGA-1G-CML-live/projects/reference_switch_nf1_cml.
I have a few questions.

First is that where can I find the TOP module of this design?
By Looking to NetFPGA-1G-CML-live/projects/reference_switch_nf1_cml/hw/nf1_cml/system_axisim_tb.v
I find name of the TOP module seems to be system_axisim(or system as I have found in another file).
However by searching the files I cannot find a module called "system_axisim".
So, where can I find it? Or by some make commands, I can build them find them in specific folders？

Besides, I follow the steps and get a bitfile. I cannot see much information related to it.
what if I want to know how many recourses the design occupies on the FPGA?(like how many LUTs)

Furthermore, is it possible to turn the project into a Vivado project?(I mean only relying on Vivado, getting rid of ISE?) By using scripts, I can only build the project in Linux with limited version.
If I can use only vivado, it can be built in more kinds of OS.

Thank you very much. Looking forward to your reply.

[Shandongwzl]

Oh, another question.
If I want to modify some parts of the design, what should I do?
For example, I want to modify the output port lookup. Should I modify this file?
NetFPGA-1G-CML-live/lib/hw/std/pcores/nf10_switch_output_port_lookup_v1_10_a
And how can I make sure that the bitfile is re-generated?
(Sorry again for my limited knowledge)