Explicit index vs implicit index

Could anyone please help me on selecting when to use explicit and implicit index.
In the context of navigating only selective relationship to reach target node , does implicit index help.

(SourceNode) - [:LINK {name='a'}] -> (TargetNode)
(SourceNode) - [:LINK {name='b'}] -> (TargetNode)
(SourceNode) - [:LINK {name='c'}] -> (TargetNode)
(SourceNode) - [:LINK {name='d'}] -> (TargetNode)

Note: i have only a single relationshipType as LINK and could have different values of property of 'name'

What do you mean explicit vs. implicit index??

I think what you're asking about is how to optimize queries to traverse only the relationships that have a property of a certain value?

If this is the case, know that you can't index the property of a relationship, you can only index the property of a node. I think you'll find better performance by changing your data model. I would recommend inserting a node in the middle, splitting the relationship into two. Or you can give more meaning the name of the relationship to also have value you're looking for as part of the relationship name.

yes, traverse only those relationship which has certain value of (relationship)property.
on relationship one can not index on property value hence explicit refers to manage outside using apoc procedure like in this doc

As best practice i came to know to have RelationshipType (rather having a property on LINK ) hence i highlighted and mention in as NOTE . At this stage we don't want to change data model . I am planning to have data migration where i can change it to a different relationshipType for each value of property on relationship.

i came across "super node" issue, how it was addresses

hence i want to know more details on index such node which has many relationships.