Just click all the links and check what you need, I'll give a concrete recommendation at the end
How long have you got? "TSA and its applications with examples in R" should cover what you need to know. You'll be able to skim the first 60/70 pages or so, and then you get to ARIMA. You can then probably go straight to GARCH. Either way, I'd say chapter 4 is unnecessary. So all in all, not doing too much reading.
Latest edition: https://link.springer.com/book/10.1007/978-3-319-52452-8
Should be able to download if your uni has a subscription, and you login with your username/password with Athens/Shibboleth.
Look up Ben Lambert for intuition on anything you don't get
Here's a couple online courses, you might prefer videos.
https://www.coursera.org/learn/practical-time-series-analysis
https://www.edx.org/course/time-series-analysis-0
I'd recommend the last link. Mainly because I personally like videos. It covers what you need to know from the start, and will probably be less intimidating since they're (presumably) trying to appeal to a wider audience than a full-on textbook.
https://prod-edxapp.edx-cdn.org/assets/courseware/v1/dc5f4b93d9fdbddb941a623e47ff47ba/asset-v1:GTx+ISYE6402+2T2018+type@asset+block/6402syllabus.pdf
Those are the pre-requisites.