Hello, I hope I can offer you some assistance.
The white pipe is the supply line and the green is the return. You may also find that the return is a different size diameter pipe, smaller than the supply pipe. If your unsure about which way the pipes connect to the fuel filter you should see an arrow on the fuel filter indicating the fuel feed into the filter.
I hope this answers your question but if I can assist further with this matter or if you have more questions regarding this let me know and I'll reply as soon as I can.
Please remember to rate my answer otherwise I don't receive any payment. If you have more questions as I said earlier please ask and I'll reply ASAP.