If the number of wires corresponds to the number of speakers then your need to determine which cable goes to which speaker. You can do this with a "toner" which injects a small signal that will make a sound in the speaker. You can also connect a AAA battery to each pair of cables. This will make the speakers move but will be hard to spot if you cannot see the speaker, The other option is to connect a receiver to each pair of wires. This will identify the speakers so they can be connected.
Is there an in wall volume control in each room that has speakers? Most people will want to control at least the volume of each room. You can connect a sufficiently powerful receiver with a speaker selector. If you want each room to be a separate zone you can do a system like Sonos which will allow access to internet music and be controlled by smartphones. tablets, and computers.
If this stuff is not your thing I would suggest you get a local audio installer to check it out and suggest the best way to get it running at the budget you have.