When the expert advisor opens orders, it can automatically set a take profit value for each one of them. In order to set the initial take profit (we refer to this as “initial” since this value as many others in other inputs can be dynamically changed during the expert advisor execution) you need to follow this format:

​[set mode: manual],[take_profit_pips_value]

This means that when you set something like manual,50 you are telling the expert to automatically set 50 pips of take profit for each opened order (by its intervention, not by the trader itself).