are there any videos on how to build a basic Dialogue system with multiple options like out of mass effect or TES?, nothing too complex just one that is on screen and doesn’t use a chatbox but offers pre-determined options
Here you go 
The ue4 dialog also offers language nativization and sub titles as well. Its a bit painful to setup tbh.
Also as I recall there is little to no control on where the sub title text is placed.
The tutorial seems like a good jumping in point.
I would just recommend to instantiate widget parts: individualizing them, so that you can
a) provide a standard press button function
b) eventually get gamepad support.
c) track player choices (via a boolean or similar).
To be completely honest. For my mental health I would design a system that works off of data tables, so I can update excel sheets and import them, and they automatically draw up the menus with questions and answers plus expected results/actions
Say we talk to a vendor and ask to browse wares, for instance. The end action would be to open the shop interface.
Say you talk to a guard and cuss at him, the end action would be him attacking or something (unless he’s a Swiss guard :P)
The end actions would probably be standardized by a secondary table or similar so you can just use an integer in the dialogue sheets to get the expected result.
An obviously important design point would then be to allow the system to carry on to the next line. Or to abruptly end. Along with a billion other things you’ll only actually figure out when making it…
Configurable dialogue content, multi-branch dialogue, plot dialogue
https://www.unrealengine.com/marketplace/en-US/product/businessdialogsystem