It was slow at first, but many showed up eventually
It was slow at first, but in the end it was a success
It was slow at first, but many showed up eventually=最初は人が少なかったけどその内たくさんの人が訪れた
slow=暇、あまり人が居ない
show up=現れる
eventually=その内
It was slow at first, but in the end it was a success=最初は暇だったけど最終的には成功した
success=成功