I didn’t look up a method (though I will do if I try again), the last one I tried I scored the outer layer to try and make sure water got in to trigger germination & just sat it in some water indoors. I think I’ve seen people poke sticks in them so it’s bottom is sat in water, but I may be remembering incorrectly!

Interesting re the sand option, I could try that next. Did you heat it? I have a heat mat so could try using that. I think I’d likely keep it indoors first year, unless it looks like its doing really well.