You can also take a look at this thread. It covers some info with regards to a Work Visa/ARC
In response to your question, @Steve4nLanguage thread link has the right process, surprisingly it hasn’t changed too much. However, make sure you are applying for a landing visa! Just a mix up of terms, not a different visa.
Once you have arrived in Taiwan and through immigration with a landing visa, you shouldn’t need to leave Taiwan since the process of landing in Taiwan with the…landing visa, is a process necessary to move forward. I think there’s a window in which the landing visa stays valid to apply for an ARC so make sure you don’t wait!