How to properly set up the structure?

I have the following task: to create several sections on the site, for example: Work; The property;
Each section will have its own fields, for example, Job - Specialty, Work Experience. In the Real Estate section - Type of object, Area, City, etc.
I can’t figure out how to set it up correctly, what should go as a category and what as a group?

I am also interested in how to correctly display the fields for adding on the user page, how to configure so that there are separate tabs Real Estate and Work and in them, by clicking the Add button, a list of fields to fill opens

Each section will have its own fields, for example, Job - Specialty, Work Experience. In the Real Estate section - Type of object, Area, City, etc.
I can’t figure out how to set it up correctly, what should go as a category and what as a group?

Each section should ideally just be a Tab. So you'd create a tab titled "Real Estate" in CB > Tab Management then in CB > Field Management create whatever fields are relevant to that tab.

I am also interested in how to correctly display the fields for adding on the user page, how to configure so that there are separate tabs Real Estate and Work and in them, by clicking the Add button, a list of fields to fill opens

Tabs and fields display are basically automated so once you've created your tabs and the fields on them as described above they'll display on profile already like that. If you want to allow them to edit the fields on that tab in profile view instead of needing to go to profile edit you'll need to use CB Core Fields Ajax and once installed you can edit your fields in CB > Field Management then under Integrations > CB Core Fields Ajax enable ajax editing for them. Now on profile you can click the field and begin editing it right there.

If you're asking about how they can supply multiple sets of fields under a section for example under "Real Estate" you have Area, City, etc.. and you want them to be able to supply 5 field combinations of Area, City, etc.. you'll need CB Field Groups for that (this works same as Joomla's repeat/subform fieldtype, but a lot more featureful). Then they'd press the Add Row button (you can rename this to Add Property if desired) it'll add a new row of those fields.

If you can provide a bit more detail or an example of what you're after I can provide more specific instructions if the above wasn't enough.

If I do TABs, will I be able to display the Job and Real Estate menu items separately? The essence of the task is to divide the posts into sections, for example on FB just post everything in a row and I want that in addition to just a post the user can choose Add Real Estate and fill in some fields. And then to display this message on a separate page "Real Estate"

There are a few more questions about the settings, should they be designed as separate posts or is it possible here? Example:
1. Is it possible to make the text automatically cut to a certain number of characters?
2. Share button - how to configure?
prnt.sc/vAG0MivRrZYp

In fact, interested in functionality and even appearance as on FB, only simpler and very important to do not all posts in the general pile and the main directions separately, so that for example refugees seeking housing and work do not look at all sorts of dogs and flowers, many are looking for missing people. it also needs a separate section ...

If I do TABs, will I be able to display the Job and Real Estate menu items separately? The essence of the task is to divide the posts into sections, for example on FB just post everything in a row and I want that in addition to just a post the user can choose Add Real Estate and fill in some fields. And then to display this message on a separate page "Real Estate"

CB Activity doesn't have real-estate fields. The best I can suggest is to use the Location feature which lets you supply a location name and address, which will link to Google maps. There's no functionality for filtering activity posts based off the feature used (e.g. you can't have a page that's just Locations), but you can create multiple activity streams where a steams purpose is for supplying locations to it (explained further below).

1. Is it possible to make the text automatically cut to a certain number of characters?

CB Activity already does this and it's a height based cut (about 800px). Large posts will be given a Read More expander. This cannot be customized at this time.

2. Share button - how to configure?

Share functionality does not exist in CB Activity at this time. It's planned for CB Activity 6.0.0, which is currently being worked on.

very important to do not all posts in the general pile and the main directions separately

You can have an unlimited amount of streams. They can all be separate as desired. Below is some examples of how to set this up.

As a Menu Item
1. Create a Joomla menu item with menu type of Community Builder > Plugin
2. Set Plugin to CB Activity
3. Set Action to Activity
4. Under Activity tab set Asset to housing

As a Field
1. Create a new Activity field in CB > Field Management
2. Under Parameters > Activity tab set Asset to housing

If you create both the menu and field with same asset then you'll be able to use that stream from both locations. You can adjust all the stream parameters individually from each of those (e.g. turn off comments, turn off likes, etc..). Again, these are unlimited. So you can make as many as you need. Simply adjust the Asset to something that makes sense for you (e.g. housing, missingpersons, work, etc..).