Problem in using Transitions

Hi, i'm using Adobe Premier Pro 2020 and recently i downloaded tarnsition pack from envato. Its a drag and drop system. I have to drag the transition on my files and it makes same effects as it should. The problem is creator asked to turn off "insert and overwrite sequences as nests" so i can delete the stock footage and transition will be added onto my video. But the probelm is its not doing anything.. i'm stuck with my project and its really confusing me alot. Please help! i'm attaching a video for refference. 

PS: I'm new user of Premier Pro.