According to the information in fig 1 the SRIS tube from the front side should go from the left cylinder inlet ( see the label C in fig.2) to the center cylinder SRIS outlet port. The SRIS type 2 system. Center to Right and Right to Left, all according to fig.6-13 from the manual
From left cylinder inlet
To the Center cylinder SRIS check valve outlet.
Fig.4 shows the two remaining tubes. From Right to Left (red arrow) and Center to Right (yellow arrow ) .