As of PTE 0.3.1 this is no longer needed. You can now just download the PTE version from your Steam library!
Important notice! Test servers are based in EU region, so have that in mind when switching - you might have high latency!
The number of slots open on test servers is limited, so expect connection problems during peak hours!
To take part in Public Tests, follow the steps provided below.
Goto World War 3 > Properties > Betas > Enter the code: VUM27KStMgAP