The primary wincon is to assemble infinite mana and pump it into Urza's activated ability. This will exile the library and allow you to cast anything inside it.
Infinite mana/draw combos:
Isochron Scepter + Dramatic Reversal
Paradox Engine + Isochron Scepter
Paradox Engine + Sensei's Divining Top + Voltaic Key
Future Sight + Sai/Etherium Sculptor + Sensei's Divining Top
Future Sight + Paradox Engine + Sensei's Divining Top
Once you have unbounded mana/draw, you then can use the Scepter or Engine itself as an outlet:
Infinite untaps with Codex Shredder = infinite mill (+ Windfall)
Scepter/Reversal + Copy Artifact (Scepter) + Narset's Reversal = infinite spellcasts
Timetwister + Codex Shredder (recurring Timetwister) = infinite spellcasts
Paradox Engine + Scepter = infinite spellcasts on the Scepter
With infinite spellcasts you can win with something like creating infinite swans / casting Tezz and upticking to setup for ult, remove all non-lands with infinite bounce spells, strip hands with Narset + wheel effect, and then play out all your stax pieces and pass turn holding up counterspells so that your swans / teferi ult can kill them.