Someone on reddit responded to me but the issue was that I was missing the bolded pieces of information in the text below:

data.raw["accumulator"]["accumulator"] .energy_source. buffer_capacity = "50GJ"
data.raw["accumulator"]["accumulator"] .energy_source. input_flow_limit = "500MW"
data.raw ...

Apologies, this is a super basic question but I know basically nothing about modding or the lua language. All I am looking to do is buff accumulators. Ideally I would like each basic accumulator to store 50 GJ rather than 5 MJ and also I would like accumulators to charge/discharge x10 faster than ...