Not sure if there are any mistakes in the instructions

[kwfine]

Dear teachers,

Before the examination begins, it is usual that the senior examiner
or the supervisior of the examination center will announce some instructions to the candidates.

I would like to ask if there are any grammatical mistakes in the following sentences:

1.
Unless given permission by the examiners, candidates are not allowed to get anything out of their school bags after the examination begins.

2.
Raise up your hand if you are not sure about the instructions.

3.
Place your stationery on your desk.

Could you help me please, teachers?

[billmcd]

[QUOTE=kwfine;612406]Dear teachers,

Before the examination begins, it is usual that the senior examiner
or the supervisior of the examination center will announce some instructions to the candidates.

I would like to ask if there are any grammatical mistakes in the following sentences:

1.
Unless given permission by the examiners, candidates are not allowed to get anything out of their school bags after the examination begins. OK

2.
Raise up your hand if you are not sure about the instructions.

3.
Place your stationery on your desk. OK