There will not be a Schedule A unless your itemized deductions are more the  the standard deduction.

For 2018 many taxpayers that itemized in the past will find that they can no longer itemize because the standard deduction has doubled so all of their itemized deduction s no longer exceed the standard deduction.

Only if all itemized deductions exceed the standard deduction will it be of benefit.

Not all itemized deductions count the full amount. Medical expenses are reduced by 7.5% of AGI so if your AGI is $30,000, for example, then only medical expenses more than $2,250 would be an itemized deduction.

The 2018 tax law also caps the total of Sales tax OR State and local income tax, Property (real estate and personal property) taxes at $10,000.

You can check the actual amount of itemized deductions by using the Search Topics for "itemized deductions, choosing" (under "My Account, Tools" in the online versions). Click on "Change my deduction". That will display the actual amount of itemized deductions vs. the standard deduction. (Be sure to uncheck "Change my deduction" after checking it so you do not lock in the wrong deduction.

2018 standard deductions

$12,000 Single
$18,000 Head of Household
$24,000 Married Jointly

Add an additional $1,300 for over age 65 or blind
This amount increases to $1,600 if the taxpayer is also unmarried.

Is there a worksheet which shows the details of the deduction amounts entered versus what is allowed?

Yes, but unless you exceed the standard deduction it won't show in the list of forms. Do an 'open form' and enter Schedule A  in the search box and you'll see the details including exclusions.