Some stations have more than two platforms and this design allows you span this bridge design over multiple platforms, the main design only allows you to build the bridge connecting two platforms.
As this is an add on there are no build instructions but the build process is 95% the same as the main item. So use a bit of common sense and you will have this made in no time at all.
The main bridge can be found with this link. https://www.cgtrader.com/3d-print-models/hobby-diy/hobby-accessories/model-railway-modern-foot-bridge
The centre spans add on can be found with this link. https://www.cgtrader.com/3d-print-models/hobby-diy/hobby-accessories/model-railway-modern-foot-bridge-add-on-extras
use this link to join CGTrader and download my designs.
https://www.cgtrader.com/designers/PJD1974?referral_id=3218445