Watch the episode before, I would recommend watching the whole show. The Walking Dead is one of my favorite even if it took a while to get started in the first few seasons. I don't need to rank these seasons because they have progressively got better (four may be better than five but it's tough).
The new episode took a different approach. The shot from the end of season five where Rick kills the abusive husband and father Pete fades into black and white. It takes a while but I recognized pretty quickly that they had jumped in time. I thought they would simply stay in the future but they showed quickly that it would go back and forth. They caught us up to the crazy situation that appeared in the color future.
A giant valley of walkers had protected the homes of Alexandria and Rick's plan to direct them elsewhere leads to some intense action that will continue on in the second episode.
I have high hopes for this new season and only a vague idea of where it is going from the comic books. I like that they have varied enough to keep a few surprises. Sometimes it is advisable when making an adaptation so as not to distance readers since they already know it but some readers want to see it exactly the same. I like surprises and I will continue watching this hows as the new problems arise.