Sampler as a beatmachine like VDJ8

I really love Rekordbox, but there is one thing missing.

Mixing two songs together I want a steady beat sync with the master. In VDJ 8 I can play instrumental samples like Kicks and HiHats.

How does this work in Rekordbox. I already tried to record a "bass sample" and load it into the sample bank. But it is not completly synced when playing it as a sample.

Where can I downlaod a easy "Bass" "Hi Hat" and "Snare" sound to create with them in loop some new transitions?

So it looks in VDJ 8.