Angel of Destiny is a weird card. Buried in a mountain of text, what it essentially does is prevent all of the damage we'd deal to our opponent (in a weird, triggered way) while also gaining us life equal to the amount of damage we deal to our opponent. Then, if we can get up to 35 life, Angel of Destiny kills whomever it attacked during our end step. As such, the primary goal of our deck is to attack with Angel of Destiny and get up to 35 life.
Outside of Angel of Destiny, our most important win card is Lyra Dawnbringer - an Angel lord that also gives all of our Angels lifelink. While giving our entire team lifelink is obviously helpful in our goal of getting to 35 life to win with Angel of Destiny, there's also some sneaky synergy between Lyra and Angel of Destiny. Let's say we have both on the battlefield and attack our opponent. Angel of Destiny hits for six as a 3/7 double strike with lifelink, and Lyra Dawnbringer hits for five. Because Angel of Destiny's lifegain trigger is not lifelink, we actually gain life equal to twice the damage we deal to our opponent. So this attack, with no other help, ends up gaining us 22 life, which might be enough to get us to 35 and win on our end step with Angel of Destiny.
Usually, you don't need some crazy combo to get up to 35 or more life for Angel of Destiny. There is a pretty good amount of removal in this deck and also some beefy blockers so we shouldn't be taking too much combat damage. That means the life gain from Heroes' Reunion, Angel of Destiny, Invoke the Divine, and more should stick. Realistically, you want to only have to attack once with Angel of Destiny and anything else you might have in play so the opponent doesn't have time to find an answer. Alseid of Life's Bounty can protect it if you happen to have one, though.
Of course, it is totally possible to win without angel of destiny entirely. Something as simple as Emeria's Call
with a Lyra Dawnbringer in play is going to win the match very quickly if the opponent doesn't have an answer. Speaker of the Heavens can also grind people down if it sticks around.
Finally, Mazemind Tome is a great value card for this deck. It is our only source of card draw and can help us find our main win condition cards. Also, it gains us life! What's not to like?