Suppose $\pi :E \to B$ is a fibration with fibre $F$ above a chosen base point. Then I am trying to solve when a map $f$ from a manifold $M$ to $B$ lift to a map $g:M \to E$. The answer given is they are cohomology classes of form $H^{n+1}(M;\pi_n(F))$. I am unable to prove this.
In the special case where the manifold $M$ is $S^n$. This is equivalent to asking when is an element of $\pi_n(B)$ in the image of an element of $\pi_n(E)$. Now using the long exact sequence of homotopy groups for a fibration we get that corresponding element of $\pi_{n-1}(F)$ has to be zero. But this is precisely $H^{n}(S^n;\pi_{n-1}(F))$. But I am unable to prove in the case of a general manifold. I am guessing the idea is to use the CW structure of manifold but I do not really understand how. if anyone can give any hints it would be great. Thanks.