Some people clean the husk others don't. I never have, other than to make for easier handling. The way I look at it, it's all going to compost and be used by the plant. Neither I nor my family has had failure of seedlings due to fungus or such. That's not to say that all seeds grow, some don't.

The common way of helping the seed is make an opening in the husk. I used a pair of chicken cutting sears.
It's something like cutting a toe nail. You want to cut 'with the curve' of the husk, not into it. Cutting straight into the husk can damage the embroy. Just snip a small piece off following the curve. About halfway along the roundest side of the seed.

In my later years I quit this practice of nipping the husk altogether and just started at this point.....
Both ways work.

My family has always used potting soil instead of water with excellent results.
Either a plastic bag or a plastic container with a lid works very well.
Add the potting soil, then nest the seed husk in the soil, covering it. Add a bit of water then put on the lid or seal the bag.
A window sill is a good place to keep it.

Waiting for a month to see growth is common. Sometimes sooner sometimes a bit longer.
This young plant is very sensitive to handling. Do use extreme care in removing it from the bag and planting it in a pot. Even adult plants well react to their roots being disturbed.
If your useing a plastic container like a butter tub, the transplant can be a bit easier. Either way, be careful about handing the plant.

At this point the leaves could shrivel up on you. Being taken from the mosit insides of the bag into the open air. Especally in the dry atmosphere of a home.
To prevent this a couple of things can be done. One way to allow the leaves to harden a bit, is to cover the newly planted mango with a plastic bag. We usually just pulled them over the top of the plant and tucked the edges in under the pot, yet leaving some opening for new air to enter.
By doing this, it give the new growth plenty of moisture and some air ciruclation. After a few days the plastic can be removed.
Another way is to mist your new plant several times a day.

Do not over water during any of it's growth, but keep the soil moist. The plastic bag or lid on a plastic container will help with that. After transplanting keep the soil moist. Even after you remove the second bag from around the trans planted pot.
Simulating their natural envirorment is what I guess I'm trying to say, is the best way to grow your mango.