Tab Highlighting / Focus order

Thank you. What you're saying makes sense. Unfortunately, the issue is the yellow highlighting box, and even with a custom focus order, if you keep pressing tab, you'll start to get other areas of the player and the screen even into Edge (in my case).
I imported the old player that was used, so although I'm stuck using a classic player (not just selecting classic player in my current version, but actually importing an old one from a previous project), I can use the tab key to move to the next slide without using a done button and with no highlight anywhere. Though I would have been happy using a button, the software we are simulating is operated by keyboard only, mainly enter and tab. I'm assuming there is a change in the coding of the player XML file somewhere that either engages the use of tab  key as an accessible feature or disables it? Since I'm not going to  compare the codes line by line, and I'm sure it's changes a lot since my older project.. I'm happy with this 'solution'. For the future though, I'll bear the custom order in mind when clients are happy with the yellow highlighting boxes. It's not a bad feature, but I'm surprised the tab key is used for this, it would be good to have a choice of using a chosen key to help highlight where someone is if they get lost. I understand why it's the tab key, but unfortunately so many systems use the tab key for data entry, and clients may not want the yellow box at all because it doesn't appear in the real thing.
Thank though for taking the time to answer.