We know that the Urinary outlet can only be purified with water after relieving oneself.

1) How many times should we should wash it at least to purify it?

2) Why there is no ruling or explaining about the way of washing it?

3) The way of washing it?
I mean just simply pour on it from above without touching. Or we have to touch it, squeeze and rub it with hand and only then it will be purified?
Also do we have to clean and wash little bit inside the opening of it to make sure it is purified?

There’s clear rule about it.
You need to just pour water once on the place, with no need for rubbing, and no need to wash the inside.

Ruling 62. The urinary outlet does not become pure with anything other than water and washing it once is sufficient, although the recommended precaution is that it should be washed twice, and it is even better to wash it three times.