At each stage of development, a character gains one ability, a core asset to their character, which then serves as the foundation for various techniques.
These 'abilities' are general capabilities of the character, like control over an element, or a specific special power. Something generic with a fair amount of potential for specific techniques within it.
Some abilities will have a minor benefit in and of themselves (especially Zanpakuto abilities) while others will be purely 'entry' fees to access powerful techniques. (Which it is depends on the ability itself. The staff's key focus in these matters is balance.)
Whether you base them on your Abilities or on something else, technique's are there to give you an edge in a fight.
Each race gains a number of techniques for free with each Stage of their power. These free techniques must be tied to the ability gained at the given Stage.
Beyond those given for free from your Stages, each stage also grants a number of additional techniques available for purchase. Each additional technique so purchased costs 100 EXP x the stage level that gave it. (Stage 1 techniques cost 100, stage 2 techniques cost 200, and stage 3 techniques cost 300)
A technique is, simply put a specific application of power to some effect. It could be based on your Ability, on your weapon(s) of choice, on unarmed combat, on Hoho, on Cero if you have it, virtually anything your character has accessible to them can be technique fodder. In the update board, request your techniques, and the staff will help balance them (either down OR up, as required.) Note that in some cases, a technique may need to be divided into more than one technique in order to have similar power/effects.
Techniques frequently cost stamina per use, although there are cases in which they do not.