DragonKing: That dice chart's an easy one to answer. Click it!

What isn't so obvious is where to click. If it's white to move then click whichever pair of dice you want. If you're creating a new match or starting a new game then it matters which pair of dice you click. If you want to be the one starting tha game then click the lower and leftmost dice that gives you the number you want, ie. below the doubles. If GnuBg is to start then click the same combination but in the top left half, ie. above the doubles. for instance, clicking 2-4 will mean you start while clicking 4-2 will have GnuBg starting.

If by "playing through a game record" you mean manually entering the moves ... the human vs human should do the job just fine when you create a new match. If it's not working I don't know why. What does it do/not do?