Take it easy on me
 

How do I know which of those is my X5? E53, E70 etc..

Honestly I think this is probably the most readily available resource.


First generation (E53; 1999–2006)
Second generation (E70; 2006–2013)
Third generation (F15, F85; 2013–2018)
Fourth generation (G05; 2019–present)

or look on Realoem.com
You should check that site out for lots of other reasons as well.
You may need part numbers at some point.