As stated in the rules a run starts when the play button is pressed on a level

Well I tried but was rejected

This game requires runs to be verified, and a moderator has rejected this run. Reason: A demo speedrun is not acceptable for full game boards.

The 3ds has a demo of the game. Though demos on the 3ds have a limited amount of plays so theoretically not a whole lot of runs could be done

What if I wanted to run the 3ds demo of the game? How would I submit it?

How do I specify that?

I wanted to submit a run of all minigames from the dsiware version of the game. Would I submit this as a new game or submit this under the DS category?

https://plantsvszombies.fandom.com/wiki/Plants_vs._Zombies_Nintendo_DSiWare