How to setup trailing SL, once the position is taken

How to setup trailing SL, once the position is taken.I tried both SL and SLM, don’t see any such options except for BO, i presume, once the position is taken, this is not an option any way

Trailing SL is only available with BO. You can use CO or SL and SL-M orders but you will have to manually trail your SL as price moves in your favour.