The basic config. of T3 as an IFT is quite standard. But in this case, it seems as though a re-build of it to suit the surrounding circuitry is in order. I would approach that task in the following way . . .
1. Identify the primary and secondary windings.
2. The cct. shows the 'lower end' of each winding as decoupled to gnd. (C17 and C15).
It will be important to arrange the phase relationship between pri. & sec. so that the capacitive coupling between them is a minimum. It is usual for that to be so, so that the coupling, pri. to sec., is predominately inductive.
3. Connect the appropriate wires from each coil (4 + 1 in total) to tags on T3 such that those tags selected are conveniently adjacent to the wiring / components in the circuitry around T3. (It obviously matters not if the selected tags are not the same as those originally used. It's the electrical connections that matter; the physical arrangement as to whatever is convenient).
4. Fit T3 to the chassis and wire it in.
5. Check - using an Ohm-meter - that the connections now 'make sense'.
6. Apply d.c. power; check for correct d.c. voltage on V3 anode / plate.
7. Use your sig. gen. to adjust the alignment of T3 as required.
8. Finally - come back here and ask for further help, if you then find that things 'aren't right'!
And the best of luck - it usually helps!
Al.