Collect the spores as sterile as possible. Look on this forum or mycotopia.net (better, great archives) for a tek to collect spores that suits you.
Decide how you want to grow mushrooms. I would start with PF tek (google: pf tek for simple minds, great/easy, using this tek for over a decade myself).
Just injecting spores in manure won't get you far. If you are very lucky, you may find a shroom or two but in most likelyhood, you won't. Sterility is key, you are growing a fungus in a controlled environment which has been prepared to be optimal for fungi so, you should keep competing fungi to a minimum.
If you are really serious about growing, buy a couple of syringes from ******* so you can be sure your spores are clean.
You don't need to water mushrooms, their environment needs to be humid so they can take up water from the air.
If you are REALLY serious, order Paul Stamet's book 'the Mushroom cultivator'.
Good luck!
