Clone the NEO430 repository using git from the command line:

git clone https://github.com/stnolting/neo430.git

Download directly for free from TI: TI msp430-gcc compiler

Or download a copy from github

Open your FPGA synthesis tool (or just a simulator) of choice and create a new project. Add all VHDL files from the NEO430 rtl/core folder to your project. Make sure to add them to a new library called "neo430". neo430_top.vhd is the top entity of the processor itself - with all the interfaces coming out of it. For a simple start it might be better to use the neo430_test.vhd file as top entity (from the rtl/top_templates folder). This test setup only requires/provides a clock, a reset button, a UART interface and some fancy LEDs.

Now you are ready to go. Take a look at the "Let's get it started" chapter of the NEO430 Datasheet. That tutorial will guide you through creating and configuring your NEO430 project.