doc: Added section on how to open testbench in GUI

Signed-off-by: Istvan-Zsolt Szekely <istvan.szekely@analog.com>

docs/user_guide/build_tb.rst

@@ -94,8 +94,8 @@ the project. This option gives you the ability to build only the configuration
 that you're interested in, without building the rest of the available
 configurations, as well as running the chosen test program, if it is the case.
 
-If parameters were used, the result of the build will be in a folder under runs/,
-named by the configuration used.
+If parameters were used, the result of the build will be in a folder under
+``runs/``, named by the configuration used.
 
 **Example**
 
@@ -162,4 +162,32 @@ Some of these may not be fully functional with our scripts and/or projects.
 If you are an AMD user, use the **gnuwin** installed as part of the SDK,
 usually at ``C:\Xilinx\Vitis\202x.x\gnuwin\bin``.
 
+Opening a testbench
+-------------------------------------------------------------------------------
+
+If you want to open the testbench and check the block design and/or the
+waveform, there are two options:
+
+- Build the testbench using ``make MODE=gui`` and it will open Vivado in GUI
+  mode right after it builds the block design.
+
+.. shell::
+
+   $cd ad7616
+   $make MODE=gui
+
+- Build the testbench using ``make`` and open Vivado manually after the block
+  design is built and the simulation is finished. In the project folder, after
+  running ``make``, a ``runs/`` folder will be created. Under ``runs/`` you'll
+  find one or more configuration folder, depending on how you ran the ``make``
+  command. Under the folder named after the configuration is the Vivado project
+  that can be opened.
+
+.. shell::
+
+   $cd ad7616
+   $make
+   $cd runs/cfg_si
+   $vivado ./cfg_si.xpr
+
 .. _AMD Xilinx Vivado: https://www.xilinx.com/support/download.html