Hello,
 I follow the instruction and enable Dev Hub but I am still getting error 
 sfdx force:org:create -f config/project-scratch-def.json -a HelloWorldLightningWebComponent
You do not have access to the [ScratchOrgInfo] object
sfdx force:org:list --all
=== Orgs
     ALIAS   USERNAME                ORG ID              CONNECTED STATUS
───  ──────  ──────────────────────  ──────────────────  ────────────────
(D)  DevHub  dannyxxxxxx@.com           00Df4000004miAiEAI  Connected

Hi All,

We are trying to setup SalesforceDX in our company and I am stucked with a very basic understanding of the SalesforceDX architecture.
So Far we have Developer Sandbox for every developer. But from now on, we wish to have one developer sandbox and developers must create scratch orgs from this Developer Sandbox and when developer is done testing on QA Sandbox, then the changes are pushed to the production org.

In my understanding, to create a sratch org, user needs to login with Devhub org which is the production org. Every developer then needs to login with production login first to create the scratch org and then push the changes to VCS? Is my understanding correct here? If Devhub is enabled, why cannot we create scratch org from the developer sandbox? Could somebody explain the architecture? I tried to understand from different blogs but didnt get any substantial answer.

Thanks. Dev

I installed Developer Hub Trial Org 64-bit Windows option.
I created a trial project with: 
     sfdx force:project:create -n geolocation

But, when I try to create the scratch org with:
      sfdx force:org:create -s -f config/project-scratch-def.json -a GeoAppScratch
I get this:
     ERROR running force:org:create: You do  not have access to the [scratchorgiinfo] object

I've tried several suggested fixes that I found when I searched for the above error. None has resolved the issue for me.