Thanks everyone. That was great help.Now I want to refer to one of the values to do sth with it. E.G.
Add a new transaction '-37' to member 'Feynman'. How can I do this? I tried sth like this

my $account_hash = $accounts->{78};

foreach my $transactions ($account_hash){
    
        push @{ $account_hash{ transactions } }, '-42.37';
    }

print Dumper $account_hash{ transactions };
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