Can somebody walk me through why this holds from the cobb douglas function AK(t)^α - L(t)^1-α

I don't know how to obtain the steady state s(Ak(t)^α) = δk(t) from the function above

And I want to know how to get k at equilibrium k* => k* = (δ/sA)^(1/1+&)

Thanks

Edit: I cannot see to fix the TEX error, sorry