Mercurial / Bitbucket branch problem

I want to create a branch to maintain an older version of my project.

Here is what I did:
cd myprj

I want to create my branch from rev 833
hg update -r 833

hg branch newbranch

hg commit -m "made a new branch from revision 833"

It doesn't want to create the branch unless i use -f, is that normal ?
hg push -f

I think i'm already in the branch, but just to make sure:
hg up -C newbranch

Then I make a change to a file
echo "1" >> dummy.txt

Then I commit/push, expecting it will commit to the branch 'newbranch'
hg commit "Change to dummy.txt"

hg push

Now when I look in bitbucket, it appear my change went into the tip and not the branch.

Also accoording to Merucurial doc, if i want to switch back to the "trunk", i would do:
hg up -C default or hg up -C main

But Bitbucket does not have any default or main branch even though the doc seem to say it should have created 'default' on the very first commit to that project

Anybody knows what I'm doing wrong ????

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