By "The Seder" I think that you mean
the poem "Kaddesh urchatz."
That poem was made as a memory aid so people would recall all the Mitzvos of the Seder.
We don't make a bracha on the memory aid.
Kaddesh is a mitzvah and it is accomplished by saying the brachos on wine and kiddush.
Urchatz, washing for the dipping of a vegetable, is a requirement for touching and eating a vegetable. Although the Vilna gaon would make a bracha, most customs are not to. The requirement or mitzvah has nothing to do with Pesach or the Seder. Rather it has to do with how we approach touching wet (dipped) vegetables.
Karpas is a custom to inspire the children to ask about this night.
Yachatz as well.
Maggid is a mitzvah, however, since it has no measure, we don't say a bracha. (Source?)
Rachtzah is normative Jewish practice, a mitzvah d'Rabbanan for which we say a bracha.
Motzi-Motza, eating "Matzah bread", is the start of a meal for which we follow the normative practice of saying the food-bracha of HaMotzi and we add a second mitzva-bracha "Al achilas matza" for the mitzva that goes along with it.
Marror is a special mitzvah of the night for which we say a special mitzva-bracha (but not on the food part).
Korech is a reminder to join the two previous Mitzvos together. Because we are just following the Hillel custom of eating them together, we make no bracha. (Some try not to talk so as to depend on the brachos already made).