I'm very confused on how to find the 2B, can you help?

2B refers to the total area of the two triangular bases. As with any triangle, calculate the area of either triangular base by multiplying the "base" of the triangle (the length of one of its sides) by its height (the perpendicular distance from that side to the opposite vertex) and then dividing by 2. That gives you the area of either triangular base (B) of the prism. Multiply by 2 to get 2B, the total area of the two triangular bases. To that area you then add the "lateral" area (L) of the prism to get the total surface area (L + 2B).