Yeah basically you just have to pick the right wood, I like to pressure cook my wool but there isn't a point. You need to realise these things grow in nature and your not growing them like a lab.
So expect mold expect things to go bad at first but its all okay it will work out after like 6 months I mean I had like 7 different types of mold and bacteria on the log I've been showing off when j first made it now it's got only the Stipticus on it.
That's just nature and how equilibriums are made.
Now for your spawn you essentially need wooden plugs made of hardwood oak is best there's a list of species that stip likes to eat floating around. Birch is okay , you just get your wood and or sawdust to field capacity ( Google that ) and make sure it is actually wet and doesn't dry out during that time make sure its also not overly wet. You prep your log by soaking in water for a week to bring to field capacity and to get rid of the sugars in it.
Over 3% sugar and your log won't grow so it's important to soak, I changed my water every day for that week and made sure the log was held under the water by a plate.
After your spawn substrate is made you just simply mix it together with your already grown spawn or yohr spores and wait for jt to grow. After its grown you pack the spawn into holes filled into your log and seal with wax, wait another 6 months and you will have mushrooms!
Once every 2 weeks to a month soak your log to bring to field capacity and yeah don't worry if you see mold on top of your log just let it dry out a little more to kill off the surface layer of mold. Your Stipticus is right inside and under that mold, so if you let the surface of the log dry the mold gets weak and the Stipticus can grow through it. Fun fact mold may actually be a good thing in this situation. See mold starts to break down the wood on the outter layer which is denser than the inner parts. The mold breaks down that wood and when the Stipticus comes along it can eat the mold and the wood left over is already half broken down , so it can grow even faster. This may also make nutrients more available to the stipticus causing it to grow faster. Logs are great I have a couple outoods too ahahaha I'm probably going to make a huge wood pile this spring and spawn ALL of it

cuz why not?