It's the basic Leninist presentation of Leninist party policy in relation to the working class.
Where to start? First of all, the pamphlet starts out by saying in response to challenges to Marxist orthodoxy that discussion and dissent shouldn't be permitted because it leads people to have opinions that aren't sufficiently 'Marxist' enough, at least as Lenin understands it.
Second, the rest of the pamphlet is devoted to dismissing workers' self activity and arguing that workers can only be liberated by bourgeois people coming to them and teaching them the pure socialist Marxist doctrine. Not only that, but in point of fact Lenin dismisses the self-activity of workers as somehow leading away from socialism itself.
It's pretty clear that Lenin had an understanding of radical socialist party functioning that was out of line with reality, and that his understanding of Marx and Marxism were based in large part on elements of fantasy, elements perhaps generated from surreptitiously and transgressively reading Marx in far away Russia without having any actual contact with the socialist movements of Western Europe. He seems to have had no awareness that Marx and Marxism came from the socialist movement itself, that life did not start with Marx and his writings, and that Marx's writings were incorporated piecemeal into the socialist parties instead of stamped into them in an inflexible way.
Marxism for Lenin, in this pamphlet, is just another revolutionary phase, another flavor of the month for bourgeois youth who want to engage in radical politics in Russia--no organic basis needed. Lenin wanted a socialist workers' state, but didn't want the reality of the proletarians to get in the way. Unfortunately, one of the legacies of What is to be Done is some anarchists and opponents to Leninism seeing in any attempt to talk to working folks about the ideas of socialism a bourgeois vanguard seeking to enlighten the poor benighted workers, who surely are regarded by them as only being capable of having 'trade union consciousness', right?
*on edit: if you want an alternative to this sort of thinking, the Bourse du Travail movement in French Syndicalism is a great counter-weight, sometimes associated with Fernand Pelloutier.