Help a noob with Detonate Dead

I always follow a build guide every league, and in this league I tried following the Detonate Dead guide on Maxroll.gg. I never had any issues with any build except for my lack of currency, but this time I can't even get into maps. Every league I just put on gear with hp and max the resists and I can go far enough to get some currency (at least T4 or T5 maps). But with this skill tree, even though my character has enough damage and is surprisingly more fun to play than I initially thought, she has next to zero defense, and dies very easily. What am I missing here?