Implicit rule for SD-WAN zones

Hi, experts,

Understood a implicit rule for SD-WAN, but I don not know how to use it :

1. What difference between the implicit rule and the SD-WAN Maximize Bandwidth (SLA) ? or how to combine/match these two components for controlling load-balance performance ?

2. If I have many SD-WAN zones, how to configure the implicit rule for different SD-WAN zones

Many thinks in advance