Translation:The job starts on Monday.
And 始まります means to start or begin. In English we would not say "The work starts on Monday." We would say, "The job starts on Monday " Or "I start work on Monday." Rarely, if ever, would it be the sentence they chose. If they want to keep this sentence, I would drop "The" and have it just be "Work starts on Monday."
My suspicion is that since しごと is the topic, the topic is not you, and therefore, it's the work that starts on monday, not you. Maybe the very lazy construction workers, tired of people complaining about slow progress, put up a sign that read 「しごとは月よう日にはじまります。」hoping that would make people less angry?
There should maybe be possible to choose to have more kanji or something. Because as a beginner, I can't remember all the kanji we've had up to this point, and if there were more, I would have a hard time learning this at all.
I see many people complaining in the comments that there should be more kanji ... Maybe if it was possible to have a sort of "kanji mode" that you could choose to have on or off, that would be okay for everyone.
Kanji is great for reading more advanced texts, but really shouldn't be necessary at this level of Duolingo.
If you're having trouble with a sentence this basic due to a lack of kanji, understanding a conversation is going to be very difficult. Context will be all you have to determine what's being said, especially when it comes to homophomes. So try to practice Duo with the sound on, and let go of the urge to look for kanji to recognize.
Apparently there are areas in Japanese where native speakers do not use pitch accent at all. See the fascinating first answer here: https://japanese.stackexchange.com/questions/51756/if-kanji-are-necessary-to-disambiguate-homophones-how-come-its-still-used-bei Also, pitch accents vary by region in Japan. Furthermore I have read that some foreigners that have lived in Japan for a long time have never mastered pitch accent at all and can still be understood perfectly by native speakers. It seems that pitch accent is not important for communicating in Japanese unless you want to sound like you are a native speaker from a certain region of Japan or be able to distinguish the origin of a native speaker based on their use of pitch accent.
Sure. The は particle marks the subject of the sentence. The sentence you're writing has 'work' as the object, and if we wanted to write that omitting the "I" (as is very common) it would be:
月曜日に仕事を始まります or (with hiragana) 月曜日にしごとをはじまります
The particle を marks the object.