Hi Experts, transaction SPDD when SAP Upgrade?

Hi Experts,

I am working on SAP Upgrade project, and the first step task is to work on SPDD, did anyone have the experience about this kind of job? when coming to data element how can I do with the data elements? I saw some has yellow traffic lights and green traffic lights and so on, how can I handle this kind of thing?

thanks.

Kind regards

Dawson