@BEE > Welcome to the Pioneer forums and congrats on buying new equipment.
I understand there is a bit of learning curve with rekordbox and preparing tracks - we are working on new videos that will be rolled out continuously in the coming months.
I'd just likely to cover some of the important points that you may not be aware of:
Firstly, rekordbox relies on an algorithm to compute the necessary beatgrid. It does in two ways which the user has a choice between choosing. The first is Normal Analysis - this method is the general choice for electronically produced music that has a consistent beat running throughout the track. The second option is Dynamic Analysis - this method should be used to calculate beatgrids of tracks that do not hold consistent values - for example, a live drummer / live audio etc. Choosing which analysis mode to use is fairly dependent on the genre of music you play.
The second point to cover is the options to edit the track - there are buttons to shift the grid left and right, increase the spacing between beats as well as decreasing etc.
For the most part (if you play EDM) you should analyse in Normal mode and then possibly have to shift the grids on some tracks but too much editing wouldn't really be necessary.