nd1:=5;nd2:=35;nmov:=5;zeroline:=0;{You don't need to define this value, Metastock knows what 0 means}M1:=Mov(C,nd1,E);M2:=Mov(C,nd2,E);MACD:=M1-M2;MACDmov:=Mov(MACD,nmov,E);{in an exploration you don't need to state the following variable names}MACD;MACDmov;zeroline;{be careful of the placement of the last variable name in your indicator, If you use the Fml() function they default to the default settings in your inputs and give the value of the last named variable, in this case 0}{Cross(MACD,0) would be the last line of code if you want to know when M1 crosses above M2} {Cross(MACDmov,0) would be the last line of code if you want to know when the signal line crosses 0} 
Filter: colB=Cross(MACD(),0) {by using Macd() you are going back to the default MACD setting in Metastock}