Whenever your normal order is declared to be played, if your vanguard's ability can Alchemagic, you may bind a normal order from your drop zone, according to the information in that ability's text, before resolving the normal order you played. If you do, that normal order you played is resolved as the following way.
Pay the cost specified by the played normal order and by the bound normal order simultaneously.
Perform the effects specified by the played normal order, followed by the bound normal order. After playing the normal order, put it into drop zone as usual.
Essentially, Alchemagic allows to get the benefits of two normal order cards as one. it The combined effect and cost you get from both order cards is considered to be resolved during Alchemagic.