Maybe you're asking about speaker level connection?
If you were to use this type of sub connection, you'll have to connect speaker terminals of your mono blocks to speaker connectors on the sub (provided your sub has one).
The rest of your connection shouldn't be any different from the system with no sub: source to preamp, preamp to power amps, power amps to speakers.
Many, myself included, prefer speaker -level connection, and it's worth trying at least.
If you were to use this type of sub connection, you'll have to connect speaker terminals of your mono blocks to speaker connectors on the sub (provided your sub has one).
The rest of your connection shouldn't be any different from the system with no sub: source to preamp, preamp to power amps, power amps to speakers.
Many, myself included, prefer speaker -level connection, and it's worth trying at least.