Hi I was wondering what it would take for Soviet Red Empire for it to be stronger then it was in are world...
Avoid Stalin's gross error in refusing to believe the Axis would attack in 1941.
The Axis attack is only a success, not a gigantic success, stopping well west of OTL's reach with about half the OTL casualties. In 1942, the Germans get pushed back. Hitler is overthrown in late 1942. In June 1943, Germany makes a separate peace with the USSR, agreeing to Soviet control of eastern Poland, Finland, the Baltics, Slovakia, Romania, Bulgaria, Hungary, Yugoslavia, Albania. All these countries are incorporated into the USSR.
(Dunno if Stalin would do this. ITTL, he doesn't have to pay even lip service to US/UK expectations.)
In October 1943, the USSR attacks Japan in Manchuria and north China. The Soviet Army overruns all Korea as well. A belt of Chinese provinces from Manchuria and Shandong to Xinjiang are added to the USSR.
...in other words how to make it work.
It can't be done. No central body can have enough timely information to control a national economy efficiently. It can run for a while, may even have a few dramatic successes, but in the long term (20-50 years) will founder under the deadweight of errors that don't get fixed. The efficient way to signal costs and demands is price information, which means a profit system, not socialism.
The Soviets made a huge effort to plan and rationalize their economy in the 1950s and 1960s, sending thousands of scientific and mathematical experts into the planning bureaus. It failed.