I used to have a number of posts on Adobe forums in Arabic where I explained all you need to do for RTL control. The whole Arabic forum was removed along with its content… unfortunately, I could have shared the links with you.
Having said that, by default, when you choose Adobe World Ready in the Paragraph Panel, InDesign will switch to default" character direction that you can select from the Character Panel fly-out menu as illustrated below…

If you're mixing Arabic/English languages together, I would strongly recommend keeping the direction on "Default" as InDesign is smart enough to switch right and left when needed.