Special Summoning a monster with the card's effect does not make a Chain Link.
The effect to Special Summon a monster cannot be applied in the Damage Step.
Previously Official Rulings
These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami. They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: 
If you wish, you may Special Summon the monster immediately after "Last Will" resolves (if activated after a monster was destroyed), or when the first monster is sent to the Graveyard (if "Last Will" was activated before the monster was destroyed). But you don’t have to, you can do it later.
You can apply the effect of "Last Will" as long as a monster on your side of the field is (or was) sent to your Graveyard, no matter which Phase it was in. As long as it's the same turn in which you activated "Last Will".
If you activate 2 "Last Wills", then you get to Special Summon 2 monsters, as long as a monster is (or was) sent from your side of the field to your Graveyard that same turn.
Last Turn: "Last Turn" is a very special Trap Card with very special and unusual rules. The most important thing to understand about "Last Turn" is that not all of its effects are applied when the Trap Card resolves. When "Last Turn" (the Trap Card itself) resolves, the activating player selects 1 monster on their side of the field, and all other cards on the field and in both players' hands are sent to the Graveyard. That is all that happens when "Last Turn" resolves. After that, the turn player Special Summons 1 monster from their Deck. After that, a special Battle Phase occurs. Then, during the End Phase, the victory check of "Last Turn" is applied. "Last Turn" sets up several effects that resolve later in the turn long after the Trap Card itself has resolved. Several other cards do this too, like "Last Will" and "Change of Heart".
Last Turn: If the turn player activated "Last Will" before "Last Turn" was activated, a monster can be Special Summoned by the effect of "Last Will" during the special Battle Phase (but it cannot attack during the special Battle Phase).