See the following FAQ for instructions to enter your medical expenses.
Your deduction for medical expenses is the amount that is over 7.5% of your Adjusted Gross Income (AGI). Enter the full amount that you paid. TurboTax will subtract 7.5% of your AGI.
The medical expenses will not reduce your tax or increase your refund unless your total itemized deductions are more than your standard deduction.
Type "medical expenses" (two words, without the quotes) in the Search box. Then click the blue link that says "Jump to medical expenses." That should take you to the screen that asks "Did you spend more than $xxxx on medical expenses in 2019." When you click Yes on that screen, it will start asking you to enter medical expenses in various categories.
If that doesn't work, please explain in detail exactly what happens when you try it, and at what point it doesn't do what I said.
I don't know what you mean by "the standard deduction page." If you are still getting that, what is the exact heading or title on the page, and what does it say? Post a screen shot if you can.