You have the balanced XLR Connector usually used for low impedence or a microphone. Impedence may not matter much anymore. You have a guitar and either you have a high-impedence input specially for guitar or you do not. They do not look like high impedence inputs on the Delta so what you have is what is left - line level inputs. So on your guitar amp you have pre-amp out or line out which is that input, but first you need connectors that plug into the Delta. Unfortunately they are phono RCA type connections and used more for stereo amp setups or consumer setups. But you can always get an adaptor to use a guitar cord (1/4" ends like a guitar cord) and plug into the phono connector with the adaptor. The three big connector is the XLR type connector and says it is for microphone. Some equipment has XLR connections (my fender new amp does) so I could use that connector because being that type of line level usually low impedence input that is what it is made for on the amp and on your Delta. The line out on your guitar amp (usually 1/4" like a guitar cord) is line level input for the phono plugs but an adaptor is needed to hook it all up together. Usually on the newer guitar amps they even have a headphone output that can be used to hook up the amp and get the simulated guitar amp cabinet sound out of it also which also would be for the phono inputs with an adaptor. (1/4" female to phono RCA type input like a stereo speaker amp receiver or amp - regular ol' consumer stereo amp with passive speakers).
Because of all of that, people tend to get an audio/interface that has better connections instead of using adaptors.
I use one on my normal stereo passive speaker stereo amp because I use an adaptor and it works fine. If I had powered monitor speakers that have either the XLR connector or the guitar type cord (but balanced) type connector I would use those inputs. So I have an XLR connector cord on one end and a regular 1/4" jack on the other end (except it is balanced which means it has a tip and a sleeve like a regular guitar cord but also another hot lead part between the tip and the sleeve (which is seen like a 1/4" headphone cord but instead of being L and R channel it is just a one channel balanced cord used usually in professional studio setups).
So except for the phono adaptors you would need, then all of that would work, and between the two units you probably have line out on the one and phono adaptor (RCA phono plug) on the Delta. Again adaptors can be used, and will work, but people get tired of using adaptors sometimes so they buy an audio/interface with better connections on it in the first place usually after that.
http://www.sweetwater.com/shop/cables/ Just one place on the Internet, and or a local electronic store that carries adaptors and cables and whatever is needed to make the connections.
Consumer electronics (stereo amp) usually has RCA phono connectors (like the Delta).
Professional electronics usually have XLR connections or line out 1/4" connections (like a guitar cord or balanced type cord).
That is about it.
http://www.sweetwater.com/store/detail/MSLCM2/ just one cord type and about any type is made. (or an adaptor one can buy).
http://www.sweetwater.com/c812--AdaptersJust have to find one that fits the connections you have. (whether on-line store or at your local electronics store or GC whatever).
I would not necessarily get Hosa cables because if you had a Neutrick combination connector in the front for mic, or guitar or synth or whatever in the front of an audio/interface they probably get stuck and end up breaking the connector to get it out or take the unit apart to get it out without destroying the unit.
Audio/interface just to show the combination type connector in the front for input they use nowadays.
http://www.sweetwater.com/store/detail/DuoCaptureEX/ But then I don't think you have such a connector as shown on the front of that unit.