if i connect AE to fog lights, is it better to put a fuse between?

^It won't hurt.

i think exactly the same, but don't know how many Ampers fuse it would be advisable

Basically using a fused relay harness will keep the AE electronics isolated from the rest of the vehicle and prevent any confusion between electronic modules. the current draw is small from the AE's so many just bypass this with no problems, however it is good practice whenever adding electronics to a vehicle to give them a steady power supply off the battery that is a +12v fused and using a piggybacked trigger for power.

Basically as long as you are using proper gauge wiring and supplying a clean signal you should be ok.

i was thinking on using a common fuse holder "just in case", like this one http://www.submarineboat.com/images/rov/fuse_holder.jpg with a fuse say 10A or 15A. or just tap into fog wires without any fuse holders?

http://www.submarineboat.com/images/rov/fuse_holder.jpg

Making the power feed fused is a good idea, 10A should be more than enough for the AE's, and connect to a good chassis ground.

weeeell, i thought i will tap into both the fog wires - both positive and negative. or am i missing something?

I would use a chassis ground for the AE's, connected to solid metal, as opposed to piggybacking the ground feed. It will avoid ground interference of electronics. Using a fused 12v line to the fog light positive feed is fine, however.

well that gonna be another challenge for me, because i have no idea where i can find this ground))

Just use any bolt location on the chassis in the engine bay, an existing one is fine, just scrape the paint off a bit where it will be bolted down, you can use about 100 locations under the hood.

And make sure you put the fuse within 18" of the fog light trigger, not the opposite way around (fuse by the headlight)