Pams has a clock and run/reset input. I understand that you slave it to the Beatstep Pro but not sync them in any way (so you're not telling pams to restart when the BSP does). To do this, I'd suggest to set BSP's clock out to a rate of 24 pulses per quarter note (or PPQN) in the MIDI Control Centre. Faster clock rates between time-synched devices leads to a more stable clock down the line.
A quick look at the BSP manual says that since an update you can use a TRS to dual TS cable to get both a clock signal and a run signal out of the clock output (section 7.2). I haven't tested this, so do that at your own risk, but if I understand correctly, it'd sync out of the box with Pams (make sure to set run input to be assigned to run on Pams). Cable to use is not a standard stereo splitter but stereo to dual mono, like the Hosa YMM261.
(the manual only talks about a clock and run signal when BSP is used as slave, but on the Muffwiggler topic people say it also works when using BSP as main and Pams as slave https://modwiggler.com/forum/viewtopic.php?t=193133)
-- dubstepjoris
Sync outputs a clock (set to 24 ppqn for PNW) and a "run gate". I'm using Befaco Y-splitters to sync my Keystep Pro or OXI to Pams: it has dedicated inputs for these sync signals. Or the other way around with the pexp-1: Pams as a master (clock and gate) to sync in of KSP, OXI or even a DAW (by using an audio input for clock and run). There's no risk in using this type of clock: I actually prefer it over midi clock.