Type a verb like opstaan and see exactly where the prefix goes — in a main clause, with a modal, and in the perfect tense.
The one thing learners get wrong: in a normal sentence the prefix jumps to the end (Ik bel je op), but with a modal it stays put (Ik wil je opbellen).
In the perfect tense the -ge- slots between the prefix and the stem: opstaan → opgestaan, meenemen → meegenomen. See it split for every verb.
Each verb comes with a natural A2 sentence and its English translation, so you see the pattern in context, not just a table.
A separable verb (scheidbaar werkwoord) is made of a prefix and a verb, like op + staan = opstaan (to get up). In many sentences the prefix separates from the verb and moves to the end: Ik sta om zeven uur op. The stress falls on the prefix, which is how you can usually recognise them.
The prefix splits off and goes to the end of the clause when the verb is the main, conjugated verb: Ik ruim mijn kamer op. It stays attached (whole) when the verb is an infinitive — for example after a modal (Ik moet mijn kamer opruimen) or in a 'te' construction (om op te ruimen). In a subordinate clause it also stays together at the end.
The past participle keeps the prefix and puts -ge- in the middle: opstaan → opgestaan, meenemen → meegenomen, opbellen → opgebeld. The auxiliary is usually 'hebben', but verbs of movement or change use 'zijn' (Ik ben opgestaan). This tool shows the right one for each of its 36 verbs.
Listen to the stress: in a separable verb the prefix is stressed (ÓPbellen, ÁÁNkomen). In an inseparable verb the stress is on the stem (verKOPen, beGRIJpen) and the prefix never splits off. Common separable prefixes include op, aan, uit, mee, af, in, terug and voor.