I am working on a movie for my daughter which chronicles her whole life. I began by inserting various audio clips and titles/credits because this is the backbone of my project

The problem I've encountered is that I can't seem to enter video where I want to. I inserted the first video clip midway throght the timeline but the clip was placed at the beginning of the movie by default. Furthermore, I can't drag the clip to another part of the timeline. To I have to insert video/picture clips in chronological order. Can't I insert a clip where I want to?