Please give steps to convert from Quicken 2007 to Quicken 2019

Use this link.  It has the steps.  How to use an intermediate version to convert to a newer version 

https://www.quicken.com/support/how-and-when-use-intermediate-version-convert-older-versions-quicken 

Also FYI - If your Quicken was before 2010 you should have several files making up the data.  The main data file ends in .QDF.  All Quicken versions prior to QW2010 store your data in a series of files all sharing the same filename but with different extensions like  - .QDF .IDX, .QEL, .QPH  and all 4 of those files were rolled into a single-file .QDF starting in 2010.