How to create quests

I am new at doing this. I am working in the third person template and I want to do quests for my player. I am stuck on how to do this. Could you please help me with how I would set this up. I have 20 doughnuts to collect and would like one quest to be to collect all of them and then what I want is another quest to come up after all doughnuts have been collected. I like working only in blueprints. I would appreciate any help. even pictures would help. could you also tell me which graphs to put info in please.

There no build in quest system, you need to create your own. There many ways how you could approach it. But there some brief example

If you want collection quest system best would be if you tie it with you inventory system. So you can make quest a structure, here some info how to use it:

https://forums.unrealengine.com/development-discussion/blueprint-visual-scripting/28614-how-do-blueprint-structures-actually-work

Now in game mode you would hold array of quest structures, in structure you would have Item class-Integer map:

With collection information, with class as key and integer as variable.

Now in inventory on pick up you would search thru quests and maps in quest, see in item is part of quest and mark progress of the quest, if all items are there mark quest as completed

You could also make quest a actor that you spawn or place on the level and put quest control in quest class blueprint. there many ways how you can approach it

When oyu design this kind of system you need to feel like engine designer, that you make system not for end user but developer, so you need to provide all API and feature for making quests.