How to reuse old cooler?

Hey guys,

I'm in the process of rebuilding my Alienware area 51 r2 and I'm currently trying to retrofit the old Alienware aio cooler to the new z490 motherboard.

The old mounting bracket for the Alienware cooler doesn't fit as it's not compatible. I'm wondering how were people on here able to mount their cooler onto.their motherboards? Did you guys get a separate mounting bracket or am I missing something?

Thanks in advance!