The Summoner is close / long range character, with no real mid range options. He is able to bounce enemies between these two ranges effortlessly however, and comboing an enemy at range can make it very hard for them to retaliate. As a general rule, all Punch Moves will be close range, Kick Moves will be far and Special is a mix of the two.
The Summoner's Chain Combo starts by creating some distance between him and his opponent, then after pulling them in with an air combo, does a knockdown in front of the Summoner.
Basic Combo Strategy
Longer combos depend on swapping opponents between close and long range. Your main tools for this while on the ground are ↓↓+P, ↓↓+K (which are OTGs) and S, while swapping in the air is done with ↓↓+P, ↓↓+K, S and ↓+S. A move that complements these very well is the close (↑+S) and far (↑↑+S) Vortex, which creates a stationary projectile that lingers for a few seconds after it's cast. Great for catching enemies flying through the air.
Useful EX Moves are ↓+[P] and ↓+[K] while in the air. These cause a ground bounce which give you time to land and continue the combo.
Key: [ ] = Holding a button