The Schengen Visa is valid for what is essentially a borderless territory of Western Europe covering 26 member states EXCLUDING the United Kingdom and Ireland. The rules regarding the issuance of the visa are dictated by the documented main destination (ie, the longest stay in any of those Schengen States), or in the case of multiple Schengen destinations with equal stay, the first Schengen destination you enter.
Once you have the valid visa, you are free to travel to any of the 26 Schengen States in any order you choose, should your plans change. For example, if you have scheduled business meetings in Germany (visa issued by a German Consulate) and the meetings have been rearranged to now take place in the Netherlands, or another Schengen destination, you do not have to enter Germany first. You may fly direct to Netherlands or that other Schengen destination instead..
Peninsula Visa can assist with a Schengen Visa only through the German Consulate in San Francisco provided you have had a previous Schengen Visa issued within the last 5 years and have had your fingerprints digitally captured by a Schengen Consulate and documented evidence that Germany is your main destination. Evidence of this must be shown on the previous visa label notated on that visa by the letters VIS (Visa Information Systems) and supported by a round trip flight itinerary in addition to the all other requirements as deemed by the German Consulate.
All other Schengen Visa applicants must personally appear by appointment at the respective consulate to apply.