Calculate goal expectancy from odds

Please can you give me anny input how to calcluate goal diff from bookie odds (we take real probability from odds, but dont know to use it in distrubution) using skellam distribuiton, like they do it na web /en/betting/line-making. We also strugle to get posibly Goals Sum from odds Over/Under. Any advice is welcome. We know calclulate poisson, we only need that input from bookie odds and from under/over odds to get probabily goal expectancy for Team 1 and Team 2.