Culture is probably the least tangible thing in a company. It emanates from the founding team, then it's nourished by the newcomers getting onboard.
While this is something hard to grasp, it does not mean it's not something worthy of your time. Quite the contrary!
Culture has the power to make or break a company. Great cultures usually lead to great successes. Toxic cultures usually lead to low talent attraction and a massive turnover.
Focusing early on culture is mandatory, it'll help you set the right foundations to grow your company and to make the right decisions.
This section is meant to guide you, to show how and why some companies built their culture.
Remember not to copy but to build your own culture. Inspiration is great, copy/pasting, not so.
As a good extension of this intro you can watch this talk by Tim Brady, partner at YC:
I joined comet almost 3 years ago now and the company was a few months old at this time.
Culture was not something we focused on as we were a bunch of people working from a flat.
As we grew though, we felt the need to define this culture in order for it to guide our growth and the decision we would take in the future. Here's a slide deck explaining how we did it (congrats to Corentin Grange and Virgile Raingeard for their amazing work!)