Multiple indis have to agree at the same time to open position, you can observe this in indicator chart where below indicator values it says "is long/short entry allowed". When all open slot indis say "yes", the position is opened.

With closing it is a bit different - for a close event to happen, one indi signal is enough to close the position, although you might have many exit slot indis.

For example better bollinger bands only shows Period and Multiplier to select for optimization,
but the indicator also has more parameters.
like smoothing method, base price, signal shift, indicator symbol, longer time frame etc which I cannot choose to optimize.

Also, when there are multiple entry or exit indicators (multiple slots), what is the logic?
will it buy/sell when only one of those buy/sell conditions are met, or all of them?

TIA