docs/user_guide/build_hdl.rst: Updates for first project.

Signed-off-by: Villyam <Vilmoscsaba.Jozsa@analog.com>

Author: Villyam

docs/user_guide/build_hdl.rst

@@ -849,14 +849,18 @@ The **sof** file is used to program the device.
 
 The Lattice build is in a very early version. We are just adding the first
 version of library infrastructure support.
-Currently, we only have a single early-version base design that builds almost
-like the other ones. For Lattice, there are separate tools for creating
-a block design **(Propel Builder)** and building an HDL design **(Radiant)**.
+
+.. note::
+
+   Currently, we have only one supported project --- the **ad738x_fmc** for
+   **LFCPNX-EVN** carrier board, in ``hdl/projects/ad738x_fmc/lfcpnx`` folder.
+   For Lattice, there are separate tools for creating
+   a block design **(Propel Builder)** and building an HDL design **(Radiant)**.
 
 To build a project, go to the carrier folder and run ``make``. For now, you can
-try to build the only base design we have available for
-**CertusPro-NX Evaluation Board** by entering the base design directory and
-running ``make``.
+try to build the **ad738x_fmc** project that we have available for
+**CertusPro-NX Evaluation Board** by entering the
+``hdl/projects/ad738x_fmc/lfcpnx`` directory and running ``make``.
 
 .. shell:: bash