D&D 5E Combat round break down

[Tony Vargas]

If you had to break a 6 sec combat round down how would you do it? So many seconds for action, movement, etc.

You can take your action at any point (or points if your action can be broken up, like Extra Attack) in your move, and interact with an object as part of your action. So it's not like moving is running for 3 seconds and Dash Action is moving for 3 more seconds. You're moving the whole time, if you want to be, or doing so twice as fast with Dash.

Probably the only thing that really maps well to seconds is distance moved - if you'll end up moving your full distance that round. If you have a speed of 30' you move at 5'/sec (brisk walk) while doing other things, and 10'/sec dashing (a jog, really, a full run would be half again that, a 4-min-mile sprint better than double).