Given that the goods yard is probably only going to be shunted by Down trains (ie. where the loco will already be at the correct end and can shunt using the headshunt), you would probably need a ground or shunt signal under the stop signal outside the signalbox, to authorise the movement onto the Single Line and also an advanced starter to properly protect the Single Line, if this is a regular movement.
Without the above measures, you would need to obtain a 'Line Clear' from the box in advance (in the Down direction) and exchange the appropriate bell codes, authorising you to occupy the Single Line for shunting purposes.
Similarly, if an up goods train is to serve the yard and run round in the station, the above arrangements would also be used. In such circumstances, you would either have to have a similar arrangement in the Up direction, unless again, you obtain the appropriate authorisation in accordance with the Rules & Regulations from the Up direction box in advance, for the loco to occupy the Single Line for shunting purposes.
The 'Rules & Regulations' option is probably ideal if (i) traffic levels are relatively light and (ii) you don't want to build any more signals than you absolutely have to!