Each string has its own separate bridge piece. The roller bridge might be fitted with one piece rollers or a roller and separate axle. There are five slots in which the one piece roller (or roller and axle) will locate to adjust intonation.
Intonation adjustment of the roller bridge:
Intonation can be checked manually or with a digital guitar tuner.
Each strings harmonic at the 12th fret should sound the same as the fretted note at the 12th fret. If the harmonic is flat then the roller needs to be moved forward (towards the pick-ups) in order to shorten the string length. If the harmonic is sharp then the roller needs to be moved backwards in order to lengthen the string length.
Digital tuner method:
If using a digital guitar tuner, the tuner will indicate if each string is flat or sharp by fretting each string at the 12th fret.
To move the roller for intonation adjustment:
Decide which way the roller is to be moved by using on of the above methods.
Lift the string out of the roller and move the roller into the desired slot. Re-tune the guitar and re-check intonation. Repeat the intonation process for all strings.