Here’s a quick tip. Put your first marker on the first two seconds of your timeline. Then cut a video clip and fit to it. Copy and paste the video clip (each clip is 2 seconds long) up to how many seconds you want. Then go back at the beginning of your timeline. You alternately press Arrow Down on your keyboard then M for the marker. This will mark your timeline every two seconds. 🙂 You’re welcome. God bless.