(Trying to keep my question generally applicable, if a key info is missing, let me know, and I edit it in.)

It seems like I'm going to transition into a new role in a company where I'm going to be the first person being in said role.

In software engineering many of the activities are tangentially related to eachother, so other team members are probably already doing parts of what I will have to do, so some siloed knowledge already exists on how they like "stuff" done.

Everything technical can be learned from courses, but I'm not sure how to quickly pick up the nuances coming naturally with years of experience.

The role being new, and without a senior specialist in this company I think I'll have to figure out (some of) the best practices.

This is a medior level job, so they don't expect managerial skills from me, but getting myself on track is probably expected.

I can be productive from day one, but I'm afraid of making costly mistakes which only manifest themselves down the road.

Although simply trying out different approaches before "committing" to the "best" is doable, due to my lack of deep understanding of the topic it could still result in a sub-optimal solution.

How can I accelerate my growth into this new role?