Dear Bouain,
Sending signal from FPGA to DAC and acquiring back the signal on ADC is pretty much what the default reference design does. The software is configuring the frequencies other parameters. The design is a whole, I believe you need to spend a bit of time understanding the design and answering questions as why router stars are needed. You can help yourself with simulation, the CD (Constellation Description) and the various SD (Star Description).
The place to start is understanding how the reference design works and then start to modify it. Initially I would keep the software in control of everything, implement everything as close as possible to the reference design and then, only later on I would look into having a system standalone, without life support.
These integration/engineering steps is not something we can help much with unless an extended support contract is purchased from us. I can get a sales colleague to check this options with you if you desire to take this path.
Best Regards,
Arnaud