What is the set of operations of a Turing machine?
The set of operations is what makes the machine work, i.e. read input
somewhere, write output somewhere, and change its internal state
(which includes anything it may change in its memory which can be a
tape or some other device).

In the case of a TM, that is done by the transition function $\delta$.

Now, as you wish, you may see the transition function (actually a
relation, when non-deterministic)) as the unique operation applied
repeatedly. Alternatively you may consider that each instance of the
(arguments, effect) pairs defined by the function, usually defined on
a finite number of possible arguments pairs (state, tape content),
each associated with a finite number of effect triples (state,tape
output,move), are as many separate instructions, the transition
relation being then the instruction set.

It is not a fundamental issue to decide whether you see it globally or
case by case.