Okay, let's first briefly review how a router routes.
When a router receives a packet, it examines the destination address and then examines its route table for a destination network that could "include" the destination address. If the route table has such an entry, that entry also provides "where" to send the packet to move it toward its destination. Also remember, if a router does not find a route table entry that "includes" the destination address, it drops the packet.
What else do we know?
At least on Cisco routers, the router includes in its route table (by default) all networks it's currently (actively) connected to.
So, for example, if you display R2's route table, it you show the route table it should show it "knows" of 3 networks, i.e.: 168.192.2.0/24(?), 10.20.0.0/16(?) and 10.30.0.0/16(?) (NB: for the (?)s, I'm assuming you're using class B and C network lengths.)
For R2 to direct traffic from 168.192.2.0/24(?) to either 168.192.1.0/24(?) or 172.16.0.0/16(?), it needs to be "informed" about those networks, and where to send the packets for those networks next. Static routes can provide such information,
So, take a crack at what static routes should be placed on R2. Then we'll go from there.
BTW, all the PC hosts should also be configured with their correct gateway IP.
Hint: Also, if you figure out what needs to be done for R2, same process for other 4 routers.
For a last BTW, if there seems to be a lot of "work" involved in providing all the needed static routes, yup. (Hint: there are "static routes" variations to minimize the work and that's also a reason why, except in very simple networks, we like to use a dynamic routing protocol.)
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