Um I'm not going to write an essay plan for you but I can help you out. It seems that this question wants to focus on the main features of the Weimar Republic. So hence you would have to talk about the formation of the republic (you could include the inherent constitutional problems such as proportional representation and article 48), opposition to the republic (both from teh left and right wing - dont forget the role of the army), the preseident (Ebert) and the parties that ruled in the first few years (the SPD mainly) and also the cultural and social revival during the stresemann era.
Also dont forget that major economic problems, even in the relatively good period between 1924 and 1928, were a main feature of the Republic. e.g. hyperinflation, borrowing too much, relying too much on the US for loans, etc.
