I can tell you how to look at the forms, but not sure if you are asking how to edit the state as well. 

If you need further assistance, please post again.

In the meantime, below is how to look at your tax return in TurboTax Online:

Click   Tax Home

Click   Review   if necessary to get Tax Tools on the left side-bar

Click   Tax Tools   on the left side-bar (you may need to use the scroll bar for the left side-bar to see this)

Click   Tools   on the drop-down list

Click    View Tax Summary   on the Tools Center screen

When you do this,   Preview my 1040   appears on the left side-bar            

Click   Preview my 1040   on the left side-bar

Thank you . The tax tools was greyed and no action could be performed,

However the main reason I wanted to see the preview and possibly edit (which i found out is not possible except during review for errors and correct errors) is that Turbo Tax was not able to handle a situation directly and with clarity.  Retirement income of my wife is taxed federally but not in the state for 3 years (so called 3 year rule). 

I did not know how to get there .  The solution it seems is to interpret the retirement income like 401K in one of the questions (it only specified 401 k )  that comes up  after entering 1099-R. Subsequently I saw that I can apply the 3-year rule, 

Still there is a bug because on entering the amount that is exempt from State Taxes, Turbo Tax simply zeroed out for Federal also.  However the program has a quirk, After entering zero for state I went back to the screen and re-entered the full amount and this time only Federal income was updated and did not change the State income as zero

In the first place, 1099-R was entered showing state distribution was zero and that Federal distribution is the amount on 1099-R.  The program did not handle that situation properly. However I have described the work around. Later when I was able to get to the review, then other information for 3 year rule was asked for. At that time a snippet of form was available.

When review was over I could preview the 1040 form  and subsequently filed it,

Turbo Tax hopefully will fix this problem (as well as as confusing messages) in the next year's version.

This is my first experience with trying out online and also using this forum

I truly appreciate your response. 

how is line 30 recovery rebate credit computed

There is a Recovery Rebate Credit Worksheet that calculates the amount. If you have the CD/download product or have already paid for your Online product, you can see this.

If not, then the calculation is generally like this:

1. In most cases, you start with $1,200 each for the taxpayer and spouse,

2. Then you add $500 for each dependent under 17.

3. Then you add $600 each for the taxpayer and spouse,

4. Then you add $600 for each dependent under 17.

5. You apply a limit to this sum based on your AGI, which may or may not reduce the number you have so far.

6. Then you subtract the amount you told TurboTax that you actually received for EIP1 (the first stimulus payment),

7, Then you subtract the amount you told TurboTax that you actually received for EIP2 (the second stimulus payment).

Whatever is left over goes on line 30.