While trying to solve the following problem
Let $K$ be a finite field of $q$ elements. Let $U$, $V$ be vector spaces over $K$ with $\dim(U) = k$, $\dim(V) = l$. How many linear maps $U \rightarrow V$ are there?
I came across the following claim here:
The space of all linear maps from $U\to V$ is isomorphic to $\text{Mat}_{l\times k}(K).$
Could someone link me to a proof of this result?