Here's advice for some common problems in Premiere.

There are gaps in my movie...
This is a common problem for amateurs like you...
To solve the problem, choose the Multitrack Select Tool
and then click the clip just to the right of the gap. This tool will select not
only the clicked clip but also ALL the clips above and below and to the right,
all the way to the end of the timeline, ready for you to drag them all to the
left and close the gap.
The Track Select Tool
is
similar, but not so useful, for it selects only clips from one track (the
clicked clip and all following clips in the same track). However, you can add
clips from other tracks if you hold down the Shift key while you click them.
Whereas the Track Select Tool makes a horizontal selection across the
Timeline, the Range Select Tool
makes a vertical selection - in other words it selects all the clips that are
present in the frames that you drag the tool across.

The video and audio are out of sync...
Audio and video clips that have been captured from a source such as a video
camera are normally linked together so they stay synchronized - if one clip is
moved then the other will move with it. However the synchronization can easily
be broken - you will have noticed this problem sometimes even on broadcast TV.
Watch out for these red markers that indicate that linked audio and video tracks
have become unsynchronized:
. As soon
as you notice a problem, try to fix it immediately. Use the link override
tool
to move one clip
without moving the clip to which it is normally linked.
Note also that you can link any pair of unlinked audio and video clips by doing
this: