To access data you use a Handle. It is just an int variable, any number convenient for you.
Using it in dataParse associates the whole dataset with this variable/number.
So, to access data later, just use this variable in functions like dataFind(),dataVar(),etc..

If format for each type of events is constant, then it might be easier to parse one big file into several datasets, per event, with parses only lines that contain the string Filter. The string is case senstitive and can cover several adjacent fields, including the delimiters. This way only lines with a certain asset name, year number, or other field content are parsed.

I personally did not try it, so I do not know the requirements for 'string Filter' and how it should look like. Experiment.

To search by date - use dataFind, but do dataSort before.
Searching by other fields will be like working with an array, calling dataVar(row,col), dataInt and dataStr. and comparing to the filter value you need.