Hello I am new on this forum,
And apologies for the very long question.

My Friend has a Grass cutting/garden/landscape business he is looking to expand after getting some local authority and corporate contracts.
Most data entry is done on paper/MS word/ with some excel spreadsheet.
Its a 3 man business with all of them entering data on the forms

Anyway his system is ...

Customer - existing or new (Name , Address, tel) -> calls buisness and they fill in a contact form(paper)
Contact form contains info about the lead that called and info about the job
Lead -> this contains info about the person that called + some info about the work they want done
Quote -> v. simple quote price for the job (possibly after a site visit and looking at diagrams/maps/design docs and other info etc)
Job -> If the Quote is accepted this will generate a list of 1 or more jobs ( A job has a description location , equipment needed , data , time etc.)
Invoice -> Each job will have a v. simple line invoice

If there business expands they will buy a full accountancy/business package etc. so the can save on accounts fees , they want to start save data now.

Question 1.

Staring the design - my first idea was to have a 1 main Table (possibly some related tables) that followed the Contact to Job through
and then info got added at each stage.

Idea 2:
Split each stage into a table and then somehow? link to the next or previous stage

Not sure how to approach.

Question 2.

On top of the record data, they have lots of Diagrams, Maps , text docs that go with each Quote/Job
etc. wondered what best way to store these items in a database was

Most likely going to use C# Gui/ MS SQL server express / Entity Framework. (this is what I am most familiar with, also 1 of the guys at the business
used MS SQL management at college)

Any help much appreciated , even if its a e.g a pointer to some other similar project or docs / youtube video etc.