I tried installing my new alpine head unit but I didn't know how to start and cut and connect to the correct wires together.
I did not want to purchase 100 dollar modifry dci to use my dash controlls so I just decided to use the normal feature. But, if I just buy the plug and play harness from modifry, can I just plug the oem harness and this modifry harness together without having to cut and solder each cords?
Please let me know asap, I am having trouble with it

 

You need a wiring harness to connect to the head unit and to wire it to the car's harness. I have no idea if Modifry's PnP harness will work without the DCI. I'd suggest asking Modifry.

 

I get that I connect my wire harness that came with the alpine to the head unit and wire it to the car's harness, but I do not really get how to connect those together, so I was just wondering if PnP will solve my problem and install it in a sec

 

yes, the PnP harness will solve your problem (but without the DCI your dash
controls won't work). An alternative is to get a generic Honda adapter
harness like a Metra 70-1721 and splice the wires to your Alpine
harness yourself. More trouble, but you can probably find the harness locally
at Best Buy -type places if you are in a big hurry and feel competent to splice
the wires yourself.
If you think you may want a DCI at some point in the future, definitely get
Modifry's harness as it will make it much easier to install the DCI later.