Jacob Hirbawi writes:

gap> Group( [(1,2),(3,4),(5,6)] );
Error, operations: power of list and integer is not defined at
id := arg[1] ^ 0 ... in
Group( [ (1,2), (3,4), (5,6) ] ) called from
main loop

It is the second possibility listed in the manual that you want:

'Group( <list>, <id> )'

'Group' returns a new parent group G generated by group elements g_1,
..., g_n of <list>. <id> must be the identity of this group.

The <id> is needed because one might want to generate the trivial
group, in which case the 'Group' function needs a hint what kind of
group is to be constructed. In order to keep the calling convention
uniform one cannot omit the <id> even if the <list> is not empty.

gap> l := [ (1,2,3), (2,3,4) ];
[ (1,2,3), (2,3,4) ]
gap> Group( l, () );
Group( (1,2,3), (2,3,4) )

He continues:

I tried mailing this to gap-trouble@samson.math.rwth-aachen.de and
trouble@samson.math.rwth-aachen.de but it bounced back. I must be
mis-remembering the name of the second forum; could someone remind me
of it please.

The correct address is "gap-trouble@math.rwth-aachen.de" without the
"samson". However, IMHO, this message belongs to "gap-forum" not to
"gap-trouble", which should be used for technical problems concerning
installation.

best wishes
Frank