Hi, when I want to create a line for the sketch of a new part, when I click down to then put dimension in of the line, the line is not visible until I click again when I place the sketch?

Can anyone shine a light on why this is happening and how do I get the line back to see where it is going?

Also, another quick query, if I want to type in the dimension I want when drawing a line or circle or whatever? How do I turn this on and off?

Please could someone help me with these matters?

Cheers