Usually in STO, there is no "order of operations". There are basically two concepts:
1) Multiply stuff. Like Shield Resistance. 10 % shield resist means a damage multiplier of 0.9. If you got 10% twice, you get 0,9 * 0,9 = 0,81 = 19 % shield resist.
Actually since Season 5 this isn't true anymore. When I last checked in January, shield resists are back to being additive. I haven't noticed anything in patch notes addressing this issue.