Provide documentation how to configure multi target functionality

[KES777]

Details are here: #713

Please provide more detailed documentation about how to configure multi target functionality. Currently I do it at a venture.

[XiaoFeijin]

It's same to me . I also don't know how to configure this part . more information is needed ASAP.

[wupeng606]

It's same to me . Please provide more information ASAP.

[tmiklu]

Same here, pls