IP forwarding not working within virtual environment due to IPTables

Question

Update:

I read https://unix.stackexchange.com/questions/126595/iptables-forward-all-traffic-to-interface and it looks like it has something to do with IPTables, duh, after following the accepted answer the traffic from PC1 could reach the Internet but still could not pass over to R1, I will need to do more digging.

I strongly suspect this is just an IPTables rule set that need applying.

Intro

I have a network set up in GNS3 with a Linux VM acting as the 'router', I'm wanting the VM to pass the packets onto the relevant interfaces after enabling 'ip forwarding' and some IPTables rules, PC1 can communicate to the Internet but not through to R1.

---

What I've done so far

Set up IP Forwarding and some basic IP Tables rules to allow for NAT.

---

Topology and features enabled

PC1 gets IP via DHCP and is connected to ens38.

---

IPTables rules

---

Expected results

R1 192.168.188.140

PC1 192.168.206.100

R1 should be able to ping PC1, vice versa, and both should be able to ping the Internet