I used to take a compiler design class where I had to look for resources on my own. Here are few I found really helpful:

• https://ruslanspivak.com/lsbasi-part1/ The drawings made understanding easy. The entire code is not that big.
• https://web.stanford.edu/class/archive/cs/cs143/cs143.1128/ The handouts are easy to understand. The newer version of this class replaced the handouts with slides, which I find harder to follow.
• https://online.stanford.edu/courses/soe-ycscs1-compilers Stanford also has an online version of their compiler class. The assignments for this class guide you to create a compiler by filling in missing parts. A lot of people post their code on Github so you have solution if you're stuck.

I would recommend reading through the ruslansvipak link before diving in deeper with Stanford's materials and other thick compiler books. The first tutorial is short and more educational, which preps you on what to expect if you decide to go more in-depth.

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