Snapping all clips together in Adobe Premiere
If you have a recent version of Premiere you can use the close gaps function, found in  Sequence > Close Gap.

For previous versions (pre 2018), try the method in this video: Deleting multiple Gaps in Premiere Pro all at once, where you add a matte layer, then drag the existing clips over it to cut it into chunks where the gaps are, then ripple delete it. Works in any version of PP.