Hi everyone,
When I switch between folders it opens new tabs, when I press Alt + Left arrow, which is a hotkey for my Go Up button. But it seems like it only accepts Alt + Left arrow. If I change the hotkey for the button Go UP to Ctrl + Left arrow it doesn't open new tabs, when I open new folders. Is there something in preferences that should be changed?
What are the commands your hotkeys are running?
(Alt + Left goes back, rather than up, by default.)
I use Alt + Left arrow for Go Up and if use the default Alt + Left arrow for Go Back, the new tabs don't open, when I switch between folders. I actually like the idea, when the tabs are opened this way. Let's say I open Folder2 and go up back to Folder 1 and the new tab "Folder2" appears above. But it is only Alt + Left, which is a hotkey for the Go Up button arrow that does that. If I assign the Alt + Left arrow to Go Back, it doesn't open the new tabs. I would like to change the hotkey that open the new tabs when I visit some folders
What's more interesting: When I click the Go Up button with my mouse moving back from folders, the new tabs are not opened. They only open, when I press Alt + Left arrow on my keyboard, whis is its hotkey 
Add the IGNOREQUAL argument if you want to stop it happening when Alt. is down.
Add the NEWTAB argument if you want to make it happen all the time, even if Alt is not down.
More detail and possibilities can be found in the Go command docs:
https://www.gpsoft.com.au/help/opus12/index.html#!Documents/Go1.htm
How should I use these commands in this situation? Should I create a new button with these commands? It's something new for me
It's entirely up to you.
Change the existing buttons if you want to change their behavior.
Make new buttons if you want to keep the existing ones as-is and have alternatives with the different behavior.
Assign the hotkeys to whichever you want. (Or you can make standalone hotkeys to run the commands which aren't tied to any buttons.)