Quick Monitor Question

I suppose you are currently using your computer speakers?  You can get adaptors for them, but upgrading to something better is a priority to make music.

Now, to your question.  Most interfaces have line level outputs which can feed any line level input.  These exist on interfaces, so you can route audio in, but also on speaker amplifiers.  So a simple stereo i/o interface will have 2 outputs that usually are arranged as stereo so you can just plug them into an amplifier.  Some speakers (like your computer speakers) have the amp built into them.  Others, like a typical home "stereo or reciever (with a built-in radio reciever) are separate components - amp and speakers. 

Most interfaces have 1/4 inch connections.  Many consumer amps have RCA inputs.  Again adaptors or correctly terminated cables will work.  Not the place here to go into balanced and unbalanced signals, but for typically short home runs it shouldn't matter.  Your speakers can connect to the amp in an equally confusing number of ways - 1/4 inch, RCA, bare wire, or 1/8 inch.

More confusing, some speakers are going digital w/ digital ins - Spdif being the norm.  You need digital cables w/ these, not analog RCA.

Once you decide on an interface you'll simply need to buy the right cables to go to the speaker/amp system you buy.  Don't know about the Cakewalk, but you'll need the right cables.  Never forget to budget for cables - costs can eat you alive.  On-line retailers have the best price on them - guitar center, best buy etc. make an ungodly amount of money on cables.  If you have the time, buy them online.  If you are buying at a brick store, try to get the right cables thrown in for free.  They are cheap but the retailers like to make the money, so it pay to beat them up about it.

Pick your interface, find out what your amp or speakers need (the MA-7As are self-powered, I think) and buy the right cables.