There is a difference between many of the dead-end lines without shut-in facilities and other lines. The former will only have a single train staff, which is handed to the driver as authority to enter the single-line: when not in use the staff may just hang on a nail in a signal box or office. This is the only authority to enter the single-line and so ensures there is One Train Working; the General Appendix would warn against entering a single-line without a token: the warning started with ‘A driver will render himself liable to dismissal...’, the only place where dismissal was so clearly stated.
Where there are tokens/tablets/staffs (*), they must be put through an instrument by the signalman or under his instructions.
Taking the Blaenau Ffestiniog line as an example, and working from a mixture of guesswork and memory, the situation would be that a member of staff at Llandudno Junction would ring the signalman at Llanrwst and ask for permission to remove the token. The signalman would give a release, the token would be removed and handed to the driver. On arrival at Llanrwst the driver would hand the token to the signalman and receive one that the signalman had removed from the Llanrwst-Blaenau machine without any need to cooperate with anyone else. If there are shut-in facilities at Blaenau (there may not be any longer), then after using the token to operate the ground-frames and with the train safely in the siding, the traincrew will contact the signalman at Llanrwst and ask for permission to put the token into the instrument at Blaenau. This granted, the token is put into the machine and the signalman is free to send another train up to Blaenau.
To get out of the siding the traincrew have to wait until there is no train south of Llanrwst, contact the signalman and get a release allowing them to remove a token. At Llanrwst this is handed to the signalman, who hands the driver a token for the section to Llandudno that he has drawn out. At Llandudno the token is placed in the instrument and the signalman at Llanrwst informed.
* - Mostly key tokens nowadays: I am not sure if there are any electric tablet or staff sections still in use.
Hoping my memory is not at fault.