Commas after transition words

Which sentence is correct?

• First grab your toothbrush.

• First grab your, toothbrush.

• First, grab your toothbrush.

Which sentence is correct?

• Next, grab your toothpaste.

• Next grab, your toothpaste.

• Next grab your toothpaste.

Which sentence is correct?

• Then put the toothpaste on the toothbrush.

• Then put the toothpaste on the, toothbrush.

• Then, put the toothpaste on the toothbrush.

Which sentence is correct?

• After that, wet the bristles.

• After that wet the, bristles.

• After that wet the bristles.

Which sentence is correct?

• Later, clean the sink.

• Later clean the sink.

• Later clean, the sink.

Which sentence is correct?

• Finally brush your teeth.

• Finally, brush your teeth.

• Finally brush, your teeth.