should I just build a Sass app as technical founder for the first time without any proper research?

Hi indieHackers
I have been working as civil engineer for many years and then 2 years ago , I decided to start teaching myself coding.
I ended up having a full time job at one of the well-know company as full stack developer where my stack is focused on ReactJs , springboot , postgress and some internal tools. I have been working for almost 7 months now.
I really love my job and I decided to start building a very simple sass application, which is an online marketplace that connect buyer and seller to search,buy, sell and flip domains and website online.
Since it is my first time, I haven't really done any research on the product but I just want to ship something for a first time.

• the current stack I will be using for mvp will be reactJs frontend and springboot backend and the I will deploy everything on aws

what exactly first time technical co-founder should do on the tech side and marketing side?
what are the tips and tricks based on others founder experience?
I would appreciate anyone opinion and thoughts