No problem. First you have to select the column with the number. You have 3 possibilities:
1) Set the cursor to 1 in the first line after test, look at the status bar for the current line number and column number and use Edit - Select Range with appropriate values to select the column for 200 lines.
2) Switch with Alt+C or menu item Column - Column Mode to the column mode and select the number column in the 200 lines with the mouse.
3) Switch with Alt+C or menu item Column - Column Mode to the column mode and select the number column in the 200 lines with the cursor keys UP, DOWN, RIGHT, LEFT, PGUP, PGDN, ... while holding the SHIFT key.
After you have selected the number column you only have to execute Column - Insert Number with the values you need.
If you can't see a menu named Column you currently use the Basic menu. Click with right mouse button on the menu bar and select Advanced to switch to the Advanced menu.
Best regards from Austria