The bart give a great response! But to understand your question... Your split regex need a quantifier:
$_ = 'FDR [62.10060.051-F] [62.10051.381] 0 1 0';
@f1 = split/\s+\[/; #>> split only \s+ AND [ ...
@f2 = split/\s+\[?/; #>> split \s+ OR \s+[ ...
@f3 = split/\]?\s+\[?/; #>> split parts, without []...
print join(" + ", @f1), "\n";
print join(" + ", @f2), "\n";
print join(" + ", @f3), "\n";
__END__
FDR + 62.10060.051-F] + 62.10051.381] 0 1 0
FDR + 62.10060.051-F] + 62.10051.381] + 0 + 1 + 0
FDR + 62.10060.051-F + 62.10051.381 + 0 + 1 + 0
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