EAM Activity Association, which is the best way to assign all activities to each asset number?

Hi All,
I'm now working on Enterprise Asset Management. And I have to import all asset number to system.
I already have the script to import all asset number via the interface. But I'm stucking on Activity Association.
I need to assign all activities to each asset number. Could you please advise me which is the best way to activity association?

Thanks,