How to define in what order to implement layers?

Question

Software design

Suppose I want to implement the following architecture.

How to determine which of the layers to implement in the first place, in the second? What to take as a starting point? User interface, business logic or data. Is it possible to implement layers in parallel? What to focus on?

Answer 1

Parallel and iterative.

Answer 2

I use something like this:
1. Get the data.
1.1. We request from external systems or enter manually.
1.2. Result to console or log file.
2. We save the data.
2.1. We create a database.
2.2. We redirect data from external systems to the database.
3. We process the data.
3.1. We implement business logic.
3.2. The results are saved in the database or shown to the user.
4. Display the result.
4.1. We get the data from the database and send it to the user.
4.2. User interaction.
5. Repeat in the required order and with the necessary changes on all layers.