by Step Comprehensive Detailed Explanation with References
* Open Table Style Manager: Type TABLESTYLE in the command line and press Enter to open the Table Style Manager.
* Create New Table Style: Click on New to create a new table style, or modify an existing one if preferred.
* Define Cell Style: In the Table Style dialog box, go to the Cell Styles tab and create a new cell style for the total cells.
* Format Cell Style: Set the desired formatting for the cell style, such as background color (blue), text formatting, etc.
* Apply Cell Style to Tables: Apply this custom cell style to the total cells in both the existing and any new schedules created in the project.
References:
* AutoCAD Help Documentation on Using and Creating Table Styles

To join multiple polylines into a single polyline, use the PEDIT command with the Multiple and Join options.
* Initiate the PEDIT command:
* Type PEDIT in the command line and press Enter.
* Select Multiple option:
* When prompted to select a polyline, type M for Multiple and press Enter.
* Select all polylines:
* Select all the polylines that need to be joined.
* Use the Join option:
* After selecting the polylines, type J for Join and press Enter.
* AutoCAD will prompt for the fuzz distance. Press Enter to accept the default, which will join the polylines if their endpoints are within a small distance of each other.
* Convert if necessary:
* If the selected objects include lines or arcs that are not polylines, AutoCAD will ask if you want to convert them to polylines. Select Yes to convert and join them.

Explanation
the mode that should be used if you want the default value of the attribute assigned upon insertion where the attribute value cannot be changed is Constant. This option sets the attribute value as constant and prevents it from being modified during a block insertion or later.
https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/AutoCAD

Explanation
BOX 1 = WIPEOUT command with the Polyline option2.BOX2 = DRAWORDER command23
https://forums.autodesk.com/t5/autocad-forum/polyline-plan-view-boundary-of-point-cloud/td-p/6251860

UCS is a command that sets a new user coordinate system (UCS) by specifying points or by selecting an object. You can use the Object option to align the UCS with a selected object such as a line.
Based on 3 and 4, UCSBASE is a system variable that sets the name of the current UCS base. PLINEGEN is a system variable that controls how linetype patterns are generated around vertices. LWEIGHT is a command that sets the current lineweight, which is used for new objects and affects objects in the current space only.
https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/AutoCAD
https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/AutoCAD