Two or more gateway connection

I have mikrotik 2.8.26 that connected to two ISP, one use VSAT and the orther use Wireless. How to setup mikrotik so my client can use this two ISP bandwidth, how is the rule and the route ..

– ISP A 128 Kbps
|
Mikrotik – Client
|
– ISP B 256 Kbps

http://www.mikrotik.com/docs/ros/2.8/appex/scripting1|11.2.4

the problem when i use load balanching i can use both bandwidth at the same time