"Then in that case, you can begin with something simple."

In other words, not yet working directly with the flowers. Merlin's not one to judge people (he doesn't actually care enough for it) and he's quite capable of instructing someone should he be so inclined to do so. He was the one who taught the young future King Arthur, after all.

"The edge over there needs to be lined with stones to prevent the soil from falling down the slope, and then the soil leveled." He points to the area in question, which is indeed just as unfinished as he describes. Mostly because he got impatient and stopped working on it in favor of actually starting to transplant some of the flowers to the section he had gotten ready, but nobody needs to know that. "You can observe how it's been arranged as you do so."

He's not the type to hand hold though. Learn more as you go, rather than have him walk you through every step!