Trunk Branches tags for configuration management

I have never understood what trunk Branches tags means. I asked Google today to understand it.

Trunk: Main Line, working directory during development
Branches: Branch, temporary branch, customization requirements
Branches/order008
Branches/order009
Tags: publish directory without modification
Tags/release-1.0
Tags/release-1.1

Scenario 1:
Product development has been basically completed and passed strict tests. At this time, we want to release our 1.0 version and will not submit it again.Code
1. SVN copy SVN: // server/trunk SVN: // server/tags/release-1.0-M "1.0 released"

Scenario 2:
One customer wants to customize the product. We can select a version from the released database as the starting point for development.
1. SVN copy SVN: // server/tags/release-1.0 SVN: // server/branches/order009-M "Order 009"

Scenario 3:
One day, a fatal bug was suddenly found in the core of trunk, so all branches must be the same. In this case, branch merge is required.
1. svn-R 148: 149 merge SVN: // server/trunk Branches/order008
2. svn-R 148: 149 merge SVN: // server/trunk Branches/order009
148 and 149 are the version numbers modified twice.

because we manage the configuration of the website source code of our company, there is no clear distinction between trunk Branches tags. We develop data in the form of scrum. Generally, we maintain two version lines, one main line A and one branch line B. A is consistent with the running version, and B is used as the working directory for sprint development. Code can be submitted for both A and B, which is partially merged between A and B, depending on the situation. After the sprint development is complete, merge the data, select one of them as the main line, and remove the other. At the beginning of the next sprint, continue the development of the and B lines.
This is also intended to meet your configuration requirements. During line B development, line A is often changed. The Code of Line A is updated to the running environment. Chaos often occurs in the case of merging a and B, but the long pain is not as short as the pain. In exchange for long-term stability, we use the temporary chaos.