Depends what country you're in. Nominally speaking, build up productive forces to allow the capitalists to supplant the aristocracy/landlords and continue industrialized while waiting for some flavor of socialist to take leadership of the trade unions, peasants, or intelligentsia then try to help them build popularity while undermining the bourgeoisie then when theres sufficient political power/representation in the government by them ram through council republic and prepare to stomp down a counter-revolution. Usually helps to have a major power in alliance or defensive pact to help weirdly enough. Stomp the reactionaries, continue solidifying the socialists hold on power by pushing as much socialist laws through before whatever socialist leaders you have die forcing you to wait for another radical leader. Usually having the worker coop, farming collective, and universal voting laws help the most in keeping the dictatorship of the proletariat safe from legal counter-revolution from other interest groups.
If all that sounds a bit too hard still, just play France until the Commune happens and side with the commune in its event while holding a Marxist-Leninist perspective on seizing power.