David
Add an lookup object to your transformation an link it to source and target
Double click on lookup object to change it properties
select lookup source data
and set all necessary connection details
First field in lookup source is always key and second is a value
for example
if you have a field with two possible values 1 and 0 and you would like to convert it to Yes and No
You lookup table or file will look like
Key Value
1 Yes
0 No
We can create a video for you if you wish
John
PS
I think would be beneficial for you to know that we are currently adding support for direct connection for MySql,Interbase and PostgreSql databases