How do I create a routing mark
What purpose is it?
I’m a beginner.
Read this page, everything should be crystal clear 
Thanks for your answer but…
As a beginner I understand nothing of what is in the wiki.
I can not good read English sorry about it.
I want my subnet 192.168.100.0/24 for example, eth3 connect to an ISP 1(Telenet) eth1 192.168.0.1/24 Default Gateway
My other subnet 192.168.101.0/24 eth4 I connect to ISP 2 (adsl) default gateway eth2 10.0.0.1/24
How do I do
next question Where make i an routing mark?
Here is example almost matches your setup
http://wiki.mikrotik.com/wiki/Load_Balancing_over_Multiple_Gateways