I do, also.
Trading platforms vary in the way they set up the settings-inputs for Ichimoku.
On mine (with 4 inputs), the first three are the three Alan has shown above, and the fourth is for the number of periods back to set the lagging line, which is called "Chikou Span".
In the packages with only three inputs, the Chikou Span is normally permanently fixed as the same number of periods as the Kijun Sen line.
I don't display the Chikou Span, myself (and neither does anyone else I know who uses this indicator).
If you want to display the Chickou Span on yours, and if you want to use the same settings as Alan explains above, the numbers you'll need are 5-15-30-15. But you can test this for yourself by playing with it.
Suggestion: start with 5-15-30-15 and see what it looks like. Then switch to 5-15-30-30 and see whether the Chikou Span line has moved back another 15 bars (I think it will have done), and then you'll know for sure.
If you want to remove the Chickou Span line but your software doesn't allow for that option, you can probably get rid of it by setting it to be the same colour as the chart background, so that it's invisible.