Let's make sure we have the terms straight, first:
Skillchain (SC) is performed when the right
Weapon Skills are performed in the right sequence, with proper timing. Skillchains have
elemental properties associated with them. Lv.1 SC has 1 element, Lv.2 SC has two elements, while Lv.3 SC has 4 elements.
Magic Burst (MB) doesn't automatically happen; it only happens when the right spells goes off at the right time. In order to Magic Burst,
the spell's elemental affinity must match the SC's. For example,
Distortion is Water and Ice. In order to MB on Distortion, the spells used must be either Water or Ice type.
Blue Mage can help form Skillchain with either a weapon or a
physical Blue Magic spell (when using Chain Affinity). In fact, Blue Mage Lv.40+ can perform an SC by himself.
Blue Mage can also Magic Burst using the right
magical Blue Magic spell (and Burst Affinity).
* * *
Now, what is your question, exactly?
- Are you asking how to perform SC?
- Are you asking which SC to perform?
- Are you asking how to MB?
- Are you asking which spells to MB with, for a given SC?
Or is your question about something else?