Zelda actually has a couple decent follow ups at low percentage, but the middle %s are rough, because everything hits a little too hard. She's worst when trying to approach, best when deflecting approaches from not super fast characters.

Dtilt and jabs, and nairs are your combo starters. Dtilt to jab to grab does well, or dtilt to up tilt to nair. Sometimes you can get a second up tilt in, or follow up the nair with a sweet spotted bair depending on DI. You can almost reliably combo dtilt into a dsmash or fsmash. Jab is super safe on shield if you can get it out on time. Jab to dsmash gives some quick breathing room, or you can jab to grab and try to read DI for a nair, nayrus, uptilt or up smash. Get used to trying to auto cancel nair, and combining into a up tilt or down tilt/smash. Hit with Zelda's back for more damage, off stage hit with the side you want to send your opponent

Farores is great for punishing rolls, and the end lag on dins fire isn't so bad that you can't occasionally frame trap avid air dodgers trying to recover. Usually you're better off chasing off stage though. Nayrus out of shield is usually a poor choice, unless your opponent is roll heavy. Otherwise solid for punishing and adjusting momentum. Phantom is just janky, might throw off an approach if it's unexpected enough, but you shouldn't ever really need to charge it. The end lag makes it hard to capitalize on, but don't wait for something to happen when you toss it out.

All of her throws do good damage except for down throw. Opponents get plenty of time to DI away after DThrow , but you can easily punish those who don't. I find up throw more reliable for follow ups though.

Short hopped bairs out of shield are still a thing, and are probably my favorite early kill if someone's right in Zelda's shit. Farores is still super quick, so it's definitely an option out of shields, but pretty punishable if it doesn't connect. Up smash was nerfed hard this game, and is super situational I think.

Unfortunately zelda isn't a very complicated character. Shes not easy to space with because her range is kinda garbage, and she's very low mobility. Don't get caught in middle ranges and capitalize close in with her few quick moves or long duration attacks.