"I came down this morning and had a very thorough medical, and then trained with them all this afternoon," Harper told Sky Sports News after the 3-1 friendly win at North Ferriby on Monday night.
"I was told they're a good bunch of lads and paths have crossed with the gaffer a few times as well.
"It was great to see them play and 3-5-2, you don't see that very often, but it worked and they passed the ball well.
"I'm looking forward to it. It's a new challenge, a new chapter. It won't be as long as the last chapter, but I'm looking forward to it."