Manure is not needed, it does provide a higher quality substrate because it could be considered a more highly preferred food for the fungus/mushrooms. There is probably more sulphate in it, among other things... which boost qualitative and quantitative growth. Sulphate is an example of a nutrient that is important for the flourishing of many organisms. Too much of it in an aquarium typically results in quite a lot of algae.
You can always supplement your substrate with sulphate by adding a pinch of gypsum (plaster of paris powder), but this is advanced stuff and you can definitely forget about that for the while to come. Pulling off a basic grow is what you ought to aim for, trust me. It's plenty fun and the yield should make you quite quite happy. If not the first time right away, then just repeat.
I recommend you start with the brown rice flour and verm to make cakes, as described in the famous PF Tek. It's recommended all around for beginner's, I did it too and I am glad I did.
When you start getting the hang of it, I myself liked the switch to trays with rye kernels - then also using casing methods (adding a protective top layer on your tray). I made trays by crumbling cakes, because before the crumbling, those cakes have the advantage of growing very safely inside jars or filter boxes until colonized.
An example of why rye is more tricky is you have to kill contaminants in the cores of the kernels by first letting them soak and germinate a little before sterilization. Also, getting the casing right and everything... it's just added factors where it can go wrong, just a bit more delicate.
Manure is of course not harmful itself considering it's a more than decent substrate - just as long as you get the mixture right making your substrate. The way it could hurt your grow is if the manure takes too much place of ingredients that make your substrate porous. Porous meaning air should be able to flow through it like a sponge but even more open than that. If it's too solid, places where the mycelium cannot breathe, it does not want to grow.
A terrarium is an example to give you an idea of what might be used: it's closed and you can see through it to monitor what's going on and what you are doing when handling stuff. But a glass terrarium does not provide airflow by itself. You need gas exchange (oxygen and carbon dioxide), so some system would have to be arranged from the top to ventilate. I say: forget a glass terrarium - that would be unnecessarily complicating.
Look up shotgun tek. A huge plastic Curver / Rubbermaid type box can be used that is transparant. I recommend DIYing an acrylic see-through window on top, a big one in the lid to have topside view and oversight. Drill some holes in the sides, there's your airflow. It's wise to plug the holes with a little cottonball pluck.
Get perlite (buy big, not super-overpriced small baggies), wet the perlite thoroughly through a strainer to first wash it, then soak it - then let it drain well. You might want to use pre-boiled water for the soaking part to minimize contaminations. But later you should always make tinfoil coasters to put the cakes on anyway.
Sterilize the inside of your box, your so-called Fruiting Chamber is what it's called - by cleaning with alcohol. Close the lid as much as possible to avoid new contaminations.
Depending on the volume of the box, put in like 4 inches of perlite.
Your shotgun terrarium-imitation is ready for newborn cakes now. The perlite slowly lets the water you soaked with evaporate over the course of at least 3 weeks, if not 4-5. Prepare this growing chamber just as your cakes or trays start pinning, then there is plenty of time just to let the mushrooms grow in the fruiting chamber without air humidity dropping.
There are ultrasonic air humidifiers but that too is advanced. Or maybe not if you're plenty rich. I do think those can get you to 100% Rel. H a bit closer.
I built a sort of frame myself to make an extra level or 'floor' to put cakes or trays. This is risky though because it can make it hard for moist air to envelop the top floor just as well.
For the humidity, get a little meter to monitor. Should be a pet store item.
Cross-reference some different beginner TEK descriptions at the Shroomery where you should see plenty of similarities with my tek advice. Compile the consistent DIY 'recipes' wisely to get a feel for what kind of thing is generally a smart approach for beginners.
Last but not least:
Be sure to search for RogerRabbit, a Shroomery expert mycologist who made excellent tutorial video's.
And I have to ask you to use the Psychedelic Index and Beginner's FAQ in the future - these would have allowed you to post your question in our centralized Mushroom Cultivation subthread. Our crew can merge this into that thread later, especially after you get back to us on all of this.
Good luck!