InfoPath for Document Library

Open InfoPath Design >> New >> SharePoint Form Library >> Design form

Here is default user interface

Design complete form follows as

Drag and drop Textbox >> set  properties for it

Drag and drop Dropdown List >> set properties for it

Drag and drop Date Picker >> set properties for it

Drag and drop Repeating Table

Set 3 columns

Drag and drop Textbox >> set properties for it

Drag and drop Textbox >> set properties for it (note: data type: decimal)

How to create auto number repeating table:

Drag and drop Textbox >> right click >> choose Change Control and then Calculated Value from the context menu that appears …

Reference more below

In InfoPath Designer 2010, create a new Blank Form template.

On the Home tab under the Controls group, click Repeating Table and add a repeating table with 3 columns to the form template.

Right-click the first field (field1) in the repeating table and choose Change Control and then Calculated Value from the context menu that appears.

With the first field (field1) still selected, click the Properties tab or double-click field1 to bring forward the Properties tab.

On the Properties tab under the Properties group, click Default Value.

On the Field or Group Properties dialog box on the Data tab under the Default Value section, click the formula button behind the Value text box.

On the Insert Formula dialog box, select the Edit XPath (advanced) check box.

On the Insert Formula dialog box, type the follow formula into the Formula text box:

count(../preceding-sibling::*) + 1

On the Insert Formula dialog box, click Verify Formula to ensure that the formula does not contain any errors. Click OK to close the message box that says whether the formula contains or does not contain errors. Correct any errors if necessary.

On the Insert Formula dialog box, click OK.

On the Field or Group Properties dialog box, ensure that the Refresh value when formula is recalculated check box is selected, and then click OK.

Finish !!!

Save the InfoPath form template and publish it for example to a SharePoint form library.

Click ok

Save file

Input your site collection

Login to SharePoint site

Choose Form Library

Choose create a new form library

Input library name

Add 3 columns follow as

Add more column to display sum of time >> Add >> HourCount, in Function choose sum

Click Next

Publish

Preview

Input data

Open SharePoint site

Input data in SharePoint form library, you can see No.1 auto increase

Save form

Form is saved with sum HourCount.

Thanks.