Does this mean "They are going to study a lot on this Tuesday" or "Generally on Tuesdays they study a lot" or could it mean either?
The latter. We sometimes use present tense for future similarly to how its done in English (we are leaving tomorrow), but this sentence translates as habitual much more easily. I can stretch it in my head to mean "They are going to study a lot this Tuesday", but it takes tone and context.
In that case the English words to select are wrong. It should be 'On Tuesdays they study a lot', not '... are studying a lot'
How can one tell whether to translate לומדים as study or learn? (Both were accepted.) They really have different meanings in English.
They both translate to but one word in Hebrew. Additional adverbs or alternative verbs might show what the actual meaning is.
I'm still confused on the difference between learn and study in Hebrew. Is it just spelling or pronunciation? Context?
No this doesn't work. Pres. (ont. for future is with verbs of movement, generally