Planning application Geneva - process and DIY

Hi all, in the process of refurbishing my house with next step being adding a heated conservatory and digging my own pool. After being quoted 100k and 200k for a pool I decided to dig it myself and do the whole process myself.

Anyone done it themselves before? I am going to meet with the planning authority in December to discuss my plans, but I was curious to hear if anyone went through the process before. (the area is piscinable so pool won't be an issue, a bit more worried about conservatory despite the large plot of land. However, most neighbors built that extension, just not sure if heated or non heated)

Thank you!