How to clean my macbook from OTHER ob macintosh HD.

Outside of what has already been mentioned - Apples' final word on the " Other " Category >> Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.

There is a way but may not like it. Create a Bootable Installer compatible with this computer >> boot from it >> Disk Utilities >> View >> View All attached Drives >> Wipe the Drive ( not volumes indented below ) >> Format as APFS with GUID Partition Map >> Erase. Back out of DU and choose Install macOS.

Done and simple.

As to " why I have more than 100 GB in other " that question was answered earlier by Apple information quoted

We cannot trust the Storage report as to where the usage really is, 4 suggestions, especially what “Other” is…

Have you emptied the trash lately?

Look for iOS backups…

/Users/[USERNAME]/Library/Application Support/MobileSync/Backup

OmniDiskSweeper shows you the files on your drive, largest to smallest, and lets you quickly Trash or open them.

https://www.omnigroup.com/more/

Purging local backups

Please note that although this doesn't affect your remote backup from Time Machine, this will get rid of the redundancy (at least until the next Time Machine backup) that a local backup disk will provide. If you need such redundancy or are worried about the recovery of your data then you would be best served to let macOS determine when to purge these files.

Start Terminal from spotlight.

At the terminal type tmutil listlocalsnapshotdates. 

Hit enter.

Here, you'll now see a list of all of the locally stored Time Machine backup snapshots stored on your disk.

Next you can remove the snapshots based on their date. I prefer to delete them one at at time. Once my "System" disk usage is at an acceptable level, I stop deleting but you can delete all of them if you want to reclaim all of the disk space.

Back at the terminal, type tmutil deletelocalsnapshots YYYY-MM-DD-HHMMSS , where will be one of the dates from your backup. This will be in the form of xxx-yy-zz-abcdef. Try to start with the oldest snapshot.

Hit enter.

Repeat for as many snapshot dates as required

http://www.thagomizer.com/blog/2018/03/27/cleaning-up-time-machine-local-snapshots.html

tmutil deletelocalsnapshots /  # deletes all the snapshots

Seriously? No one at Apple support can tell me why I have more than 100 GB in other and how to clean it? Unbelievable!

For over 25 years as a Windows user and almost 20 as a Linux user, I have never wasted more than an hour solving a problem. Today for a mac for which I paid twice as much as for my PC I lost a whole day without success.

Congratulations Apple! You just topped my rank list for most useless support!

Actually we're just other users trying to help.