Basically yes. Each satisfying assignment (line ending with the result 1 in the truth table) corresponds to a path from the root node to the 1-leaf. If you add path after path (while not adding nodes that already exist), you get an OBDD. In order to get an ROBDD, you need to delete redundant structures and double nodes with double edges.
Edit: When adding paths, do that starting from the 1-leaf.