The most efficient solution for breaking this form into multiple tabs

Question

INTRODUCTION AND RELEVANT INFORMATION

I am software developer who must create application for managing contracts. I am very "clumsy" regarding UX, so I am not satisfied with what I have made so far.

Here is the image of the relevant part of the form I need your help with:

Let me clarify even further:

Red rectangle contains basic stuff for contract:

• Name of the investor
• Date of signing
• Name of the person who signed it
• Deadline
• etc...

Brown rectangle contains information about:

• Total price
• Currency
• Price without VAT
• Price with VAT
• etc...

Blue rectangle contains information about time order of payment -> has investor payed up front and so on. As you can see, total number of payment info is unknown. That is why I made controls at the bottom that accept data for one row in listview, and added buttons in the middle so user can add data into listview or edit/delete existing rows. If you can suggest improvement/better solution for this design I will consider it, but at the moment this is not my biggest concern.

Green rectangle is about subject of the contract ( this is the only way know how to translate it to English -> English is not my native ).

Purple rectangle deals with PDF attachments. User should be able to add, delete, open attachment. There are two types of files to attach -> contract and a bid ( again, sorry for "clumsy" translation -> English is not my native ).

PROBLEM

Although my window barely fits into screen, I find this design to be very bad. Reading through similar questions here, and reading through answers to my other questions, I think this form will cause big cognitive overload for the user.

MY EFFORTS TO SOLVE THIS

I have decided to break this form into multiple tabs. For now I have 2 tabs -> first has controls from red, green and purple rectangles, while second has controls from the blue and brown rectangle.

Although this saves space, I believe that my inexperience and ignorance are preventing me to optimize UI even more efficiently.

QUESTIONS

• What is the most efficient solution for breaking this UI into multiple tabs?
• I need to preserve space, that is why I thought of using tab control will be the best solution. If you can suggest alternative approach I will consider that too.

If further info or clarifications are required, please leave a comment and I will respond as quickly as possible.

Thank you. Best regards and Happy New Year.

Answer 1

I would like to leave a comment but it seems that only experienced users can do it. So I have decided to write an answer instead, let's see if you can use any of my ideas for your project :-)

To provide a good solution one should get more information about how this particular software is used by the users:

1. do they use some of the boxes ("rectangles") more often than others?
2. do they use any of those boxes together?
3. is any of those boxes needed to be visible at all times as a sort of reference?

So my first suggestion would be to ask users / potential users about it- without the understanding of the context it is hard to design a UI.

Let's now assume that for some reason you cannot get hold of any users of the software- if that is the case then you need to try to predict / guess how this piece of UI will be used. What I show below is only my guess of how the UI could be altered- let me know if I was helpful or if I missed the point of the problem you are trying to solve.

Most important information about the contract is presented on the left side of the screen (I assumed that it's red and green boxes). It is not tabular so it's always presented on this screen.

Every other box (rectangle) get its own tab with a name- in this way it's easier for the user to navigate between the tabs and understand what is presented in each of the tabs. If you group rectangles various rectangles under a single tab then it might be more confusing for the user (unless the rectangles are grouped in a logical way with a name that logically represents this group).