Communicate zerotier client(pc)t with a router?

i have 2 locations :

A-
router(mpls)
Group of PCs clients(connected to Router MPLS to be bale to use Database in different city)


new location B
one PC

for zerotier connection is easy to install in pc and communicat but how to connect the PC in location B to reach the router , it is important becoz this router has MPLS service.

thanks