You can't, properly. Even a 1950's tech three barrel saddle Tele is capable of more accurate intonation.
That Epiphone Les Paul Jnr is fitted with a cheap wraparound bridge implementation whose technical design would make a 1915 biplane with castor oil spewing air cooled rotary Gnome engine appear state of the art high tech.
The saddles are pot metal cast precompensated with no further end user adjustment mech. You can adjust bridge height for action or slant angle only via the two horizontal exposed grub screws at each end. Crude intonation adjustment. Just how it is.
Intonation methodology on that guitar is adjust for best compromise, or replace the bridge with an intonable one.
Don't know it bridge to body bolt spacing on that model is standard for a drop in fit, knowing Epiphone marketing, probably not. But something like this is what you want if willing to upgrade. That model guitar is intended as an (overpriced IMPO, but then Epiphone are) entry teaser to be discarded once its flaws and limitations are realised in favour of buying a new guitar rather than parts upgrading.
An expensive but nevertheless popular intonable bridge replacement appears to be the MojoAxe. On a Vintage Gibson Les Paul perhaps. Not on a cheapie.
If you're willing to have a go at intonating what you have, read this.
One of the reasons I chose to go with a conventional Tune-O-Matic on my Revstar rather than wraparound, as although the RS620's OEM wraparound is adjustable, Yamaha don't start fitting TonePros AVT-II wraparounds until the RS820CR model, which in my country is significantly more expensive than the US and at the high price point diminishing returns value end of the Revstar segment.
