How to create VLOOKUP Lists ?

Hello Everyone,

I'm working on creating a spreadsheet to help engineers produce survey reports.
i'd like to create a sheet where the engineer chooses the relevant discipline in the firstcolumn (Mechanical/Electrical) then this will inform the visible options in the next column ('Service'), which will then inform the next list ('Description') each step only showing the relevant options filtered down


Image below,

Screenshot 2023-08-29 094116.png

Any advice would be greatly appreciated,


Thanks,
Carl

Apologies, First post here,

link to sheet below: (should make it more straight forward what i'm trying to do)

we.tl/t-gkt8nk1Ize

spreadsheet attached now

There are no expected 'results'. I would just like to create a method of efficiently filtering down information into defined categories, after a certain point it will be down to the engineer to specify the issue