Befriend them and share our respective knowledge whenever possible.

Just hiding myself and pray for Geralt to fight monsters !

I'd find weapons and organize a militia in my village.

Write a book about it and sell it to a software company :)

The same procedure as at every conjunction, James. Just call the monster hunters. Will you, please?

I would recommend you Kagura Games . :DDDD

The first thing I'll do is open a store selling aspen stakes, silver, poison, and fried nekkers.

Preferably I'd be a sorceress but I feel like after not getting my Hogwarts acceptance letter my chances are slim.
Since I'm quite sure I wouldn't be able to lift a sword, I'd try to get my hands on some alchemy ingredients. I'd start a shop, make some magical customer friends so that they can get my sorry butt somewhere safe(r).

From the beginning, it was a good idea to assemble my mother's sideboard and melt it into a silver sword, save Pavel Burza from monsters, and then offer him to play a party in Gwent, and with Tortsov we will brew elixirs and sell them to local witchers and finally ask Geralt to ride a Roach.

Are you serious -- not allowing AI to compete is xenophobic itself!

About the best course of actions in case of Monster invasion:

a) Give power to AI, they'll come up with something for sure;
b) Make Jediism live and prosper and so Brothers and Sisters, by joining our tiny forces we call for help from a galaxy far, far away;
c) Otherwise, stay put.

Considering that what Alzur did was create the witchers. The deadly solution for monsters. What if we do the opposite and instead welcome all beings with love and kindness?
We could start by developing a way to communicate with them and understand their nature. This way we would learn our ways and adapt to the new situation, which happened and involve every one of us.
As we all are in it together, let's make it an opportunity to create something better and something new. (and stop calling them 'monsters'. they are very much aliens [alien animals?])

I would offer a round of Gwent to some monster. Maybe one particular troll would accept...

Probably would bought new pair of runners shoes. To be much faster than everyone nearby :)

I will disguise myself as the high priest of an ancient deity and force monsters to submit to my will or face the wrath of the Gods.