Why do you want to get into a horror game in the first place, if you don't handle horror games well? I don't see how that could work, as shocking and horrifying the player is kind of the whole point of the game.

You don’t.

The game may not be for you, and that's okay.

Have you played other visual novels? Spending some time in those may help you recognize the tropes of the genre, and then when you see them in DDLC, you'll know what not to expect since that game is specifically subverting expectations.

As other people have said though, DDLC is very intentionally somewhat upsetting, and there's nothing wrong with looking up a short synopsis to understand what to expect before deciding for yourself.

If you're triggered easily, I'm not sure if the game is a good fit for you as it does delve into some deeper, more serious topics.

The only other thing I could think of to try and resolve this issue would be to purposely spoil the plot of the game for yourself by reading summaries in advance and then make the judgement call on whether or not you believe you can handle the subject matter?

One thing I recommend for horror games is to play with a friend (i.e. in the same room). You can even figure out a way to do old-school controller-swapping (for a VN, maybe each chapter, or after a fixed time interval e.g. every 10 minutes). My partner is a huge horror buff, but also has a hard time with the longer periods of stress that horror games impart vs movies, so we play games this way.

I've tried to play it through twice and haven't really been able to get much past Act 1. Only saw hope it ended a bit though a Let's Play stream.

It's a pretty gentle horror game, if you can't cope then maybe horror games aren't for you