First — make sure you have snapping turned on.
Second – select your leftmost clip out of everything you want to move right. Click the left event edge of that clip. Now hit “ctrl g” and then type “+300” followed by “enter.” You have now moved the position bar three seconds forward. Now move your selected clip forward until it’s left edge snaps to the positioner. Now hit “ctrl shift F” (which is post ripple all tracks, markers, etc).
You could turn on ripple and set it to all tracks before moving your clip. Or — you can do the post ripple as I described above. The neat thing aobut Vegas is that you can choose your own preferred method. There are usually 3-4 ways to do anything.
Experiment a bit. You can always undo anything.
td