How to tell vowels?
Is it possible to tell which vowels are used in a Hebrew word based on any pattern? I heard someone say you can with the Arabic abjad.
Yes, in Arabic you have to write the vowel dots. In Hebrew, they are optional and not commonly used. Also, yes, there are some patterns. The most important ones are for verbs and will be explained in the relevant skills. Nouns constructed from other roots also follow patterns and therefore also patterns for the vowels. Here's a good overview: https://en.wikipedia.org/wiki/Modern_Hebrew_grammar#Noun_derivation
For everything else, this should get you started: https://www.duolingo.com/comment/7388681/Hebrew-Time-9-Reading-without-vowels