German modal verbs you'll actually say
können, müssen, wollen, sollen, dürfen, möchten — how they sit in the sentence and which one you meant.
~2 min read · A1
One conjugated verb, one infinitive at the end
Modals take the second slot; the other verb waits at the end in the infinitive, usually without zu. Ich kann heute nicht kommen. Wir müssen um acht anfangen. If you park the second verb next to the modal like English (*I must to go*), the sentence sounds unfinished.
The six you need, in human terms
können — ability or possibility. müssen — necessity (stronger than English *must* in some contexts; it can simply mean *have to*). wollen — want, including a plan. sollen — someone else's expectation: a doctor, a rule, a parent. dürfen — permission. mögen is like/be fond of; the polite request form you actually say is möchten.
Ich möchte einen Kaffee. is A1 gold. Ich will einen Kaffee. can sound blunt, not ungrammatical. Save will for when you mean a real will, not a bakery order.
Negation and exams
nicht dürfen is prohibition: Hier darf man nicht rauchen. nicht müssen is lack of necessity: you do not have to. English speakers mix these constantly. Listening papers love that mix.
What to practise
Build six sentences you could say tomorrow. Keep the same ending verb (kommen, helfen, bleiben) and only swap the modal. Then do the same in a weil clause so the modal still lands at the end: … weil ich früh aufstehen muss.