"How do I get estimate numbers entered per job?"

It is up to you if you want to use some custom Numbering Scheme in QB. Everything is already linked by the Customer:Job unique Name.

Example: I use custom Invoicing sequentially for the year, such as 2017-1, 2017-2, and QB maintains that for me. For Sales Receipts and Estimates, I let QB just number them sequentially. They are Transactions For That project, not Numbered By project, in other words.

In a different job, I did all Manual renumbering and it took hours out of the month. It drove me crazy and I would never use that system again. There already is a Provision for Account Number, for Jobs. You can use that, to Document something you don't need to use for Transaction Numbers.

Think of Invoice, Sales Receipt, Estimate, PO, etc transaction Numbering as similar to your Check Numbering. They are for easy reference. You are using a Relational database, so Names are already part of everything you will do with those transactions.