Here are all important links:
viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions
If you like to introduce yourself, to the community, go here:
viewtopic.php?f=4&t=4480
Yes, use AudioFileProcessor (AFP)
https://lmms.io/wiki/index.php?title=AudioFileProcessor
and load the phrases of your rap into them.
I favour AFP instead of Sample-track, because AFP has a lot of options, that you do not find in Sample-track, most notable; connection to mixer.
But Sample-track is the most natural feature to use for vocals, and can use huge wave-files. AFP is meant for clips up to 2 min.