Step 1: When you create a new connection, for example as shown here in Connect To hadoop article, you will get to Preview Screen.
Step 2: On preview screen, select the column in which you want to cut something. As and when you highlight some values within the column, you can get a list of suggested cut operations which is possible on that column in suggestions tab of right panel.
Step 3 : Right Suggestion panel will give you options to cut on,after or between particular position, characters etc. When you hover on these options, You will get a preview of the possible output adjacent to the column in light yellow color.
Step 4: You can select the one which you like and click on it. It will apply the selected cut operation on the column and will update the column by cutting the selected value from that column.