Creation of personal drumsets using MIDI Files

Ok, so, I'm not entirely sure if the subject line really defines my thing here, but the basic terms are in place. I want to use an MP3 File, which has been converted to MIDI, in my score via the Sampler from MDL. I'd think I could just insert it into the drumset as a note, but all the stuff online is so confusing and seems to require extra investment. I used an online converter to change the MP3 to MIDI, but now where do I go?

Simple terms would be appreciated, thanks!