CRM in Excel

Good day. The challenge is to build a CRM in Excel. Our company is engaged in the construction and sale of real estate. What data should be recorded:
date
- manager's name.
- type of contact (call/visit)
- customer name
- customer's phone
floor
- approximate age
- Reason for purchase
- the product of interest (1,2,3,4 room apartments)
- the essence of the appeal and the ability to view the history of appeals
- contact
- progress of contact (call-visit-book-purchase)
- channel of attraction (what kind of advertising)
- purchase price

What statistics should be obtained by compiling summary tables:
Effectiveness of a specific manager (viewing customer conversions)
- the effectiveness of the advertising channel (which of them attracts the largest number of interested / buyers)
- conversion of total mass of customers (sales funnel: call-visit-book-purchase)
Conversions for each advertising channel
The ratio of all channels by the number of customers attracted
- the efficiency of channels in the section of square meters (which channel attracts more one-shki, two-shki, etc.).
- the effectiveness of a particular manager in the context of square meters (which manager attracts more one-man, two-man, etc.)
- Number of attracted customers from each advertising channel by months - visualization by overlaying schedules
- the ratio of the dynamics of attracting customers with expensive and non-expensive (familiar, passed by) sales channels - visualization by means of two overlaid schedules