How to map multiple source fields to single target field

Hi ,

I have to map multiple source fields to a singlr target field. How can I achieve this ? Should i use UDF ? If so what code should be in UDF.

Below is my mapping . I just tried but I dont understand what is to be written in UDF Title which i have created.

Here I have to check source field with a string and if that equals then i need to map to target field.

Please help me how to acheive this.

Thanks

SARIKA