DOB Question

I recently purchased a coop apartment and want to do some renovations including taking down a wall, refinishing the floors and updating the kitchen cabinets. I understand that our building needs to approve these changes but what I can’t quite figure out is how we go about getting permits from the DOB and what is required in order to obtain those permits. I have received conflicting advice. Do we need to get drawings by a licensed architect / engineer (even if we know what we want to do and our contractor is licensed to do these renovations)?? That is pricey and seems like an unnecessary step. We are of course willing to do whatever is necessary to obtain the proper permits but what’s unclear is whether we can get DOB permits to remove walls without paying an architect to stamp drawings. Thanks!