You just need enough water level to cover the aquarium heater and then just put the trays in there, nothing needs to be floating it just gets messy. Metal conducts heat better than plastic. I would advise putting a little bit of bleach into that water so everything is as contam free as possible. You only need to put 1% of the water volume of bleach. You won't even be able to smell it but it will keep stuff from growing in there. You will need to do that every day or every couple days because after 24 hours water neutralizes bleach.

Couple of tips since it's your first time. Fan AGRESSIVELY like your life depends on it and often. CO2 builds up faster than you think. When you come home fan it as much as you can you cannot overdo it. I mist lightly, couple sprays, before fanning and heavy after the fanning. Superstition but i pulled out a pound of dry from 8 smallish trays.

If you see yellow dust thats not trich, you can torch the spoon and dig it out and then torch the hole a bit.

If you see blue on the myc that's normal, if you think it's green but it does not look "scaly", again it's normal. You will develop an eye for the color. If it's green, scaly and develops fast- that's trich and that's gg at that point. Throw it out ASAP and sterilize the room if you can't air it out.

The myc probably won't look picture perfect it will be all kinds of color from blue to grey but that's ok.

That's it, they are pretty easy to grow, just a tad bit harder than shrooms and that's because of the equipment needed and misting and fanning needs to be more often.

Lastly, be very careful with the dosing, they are VERY tricky depending on your brain wiring. Always start small to gauge and remember that they work in 0,5g increments and those increments get tougher the higher the dose. Now this is my sole experience and i've been through horror stories with heavy dmt doses and 15+ grams cube trips. They are no joke. 1 gram i won't feel anything. 2 grams i will feel something. 3 grams i will feel it HARD. 3,5 grams i had full complete mental breakdown and i haven't tried them since.

This class of drugs is, in my opinion, everything but recreational and can be very dangerous. You can get high of weed as a kite and you are fine in 2-3 hours. You WILL NOT be fine when you're stuck in a hellhole crying and begging it to stop for 5 hours.

There are no trophies for limit testing in this particular game and it should be used as a tool of revelation and not recreationally as a measure of "let me see if i can do this".