Manuscript status "Submitted to Journal" over a week in an Elsevier Journal
Have patience -- you're asking that many things happen within a short amount of time. Your paper needs to get through an initial administrative check whether the formatting is correct and/or whether there is any plagiarism. Then the editor-in-chief needs to assign the paper to an associate editor. And then the associate editor needs to assign reviewers. Only then does, in most system, the status change to "Under review".

So it requires three people. Any one of them might be on vacation for the week. Or they have a paper or proposal deadline themselves. Or they have a family emergency. Or they need to grade a term paper. You can't expect that they stop everything they do and turn to handling your paper. They'll get to it in due time -- I'd say you can start to get upset if it's been 3 weeks, but before that my recommendation is as stated at the top: Have patience.