Emulators

I doubt it's against the rules but, you can ask support if you're in doubt, they should be able to tell you.

Its not "bad" to try.
There are many tutorials At YouTube.

I play on BlueStacks from time to time. As long as you don't hack it should be fine.

It is indeed agaisnt the rules.
I played for a few days on blue stacks and got what i believe was a "soft" ban from that.
I used my phone to play the next day and everything was okay tho, so im not really eager to try again.