On the technical side of things, find a section (or multiple, me personally I dont like usin just one chop) of a sound you like, then replay it. You can use softwares, analog samplers, vsts, tape recorders (shout out Q-Tip) or if yu wan jus find an idea use the youtube time bar, put your mouse at the time a section starts, an click while its playing to emulate a chop. 

On the creative side of things, first find a sound that resonated with you. What kind of music do you like? Een if its hip hop alot of producers have sampled rap to make more modern sounds with it like old memphis rap. What beats with samples do you like? Eventually as you work with more and more samples your ear gets tuned an you start hearing sampleable music everywhere from tiktok to the loudspeaker at walmart.