You know that video that we're talking about? Did you watch it? He was talking to you. He was saying that you can remain stuck in the past or you can help shape the future. It's your choice, but if you want a say in the future of Britain then the time to act is now.
Nawaz said he was a firm believer in remaining in the EU, and he campaigned against Brexit. However, he said that Brexit has happened, and in his view it's time to accept that and to move on. He said that whatever political differences he may have with Brexiteers, they are his fellow British citizens and it's time to remember that he has more in common with them than he does with people elsewhere, and that the task now is to find ways of working with them.
What concerns him now is to not leave the shape of Britain's future outside of the EU to the same people who won the referendum, but instead to provide a vision of Britain's future in the world that is compatible with the values he holds. In his view to wallow in nostalgia about the glory days of the EU is to leave the initiative to others. He goes on to describe where he feels that Britain would fit and who Britain's allies should be. In talking about this, he's saying that you need to work with him to build this future.