Drawing to specific size and checking size on drawn shape

I am new to Illustrator, just downloaded it to use on an iPad.

I have started trying a few things, was struggling as I do not think that there are that many tutorials specific for the iPad, however have started to get grips with the program, however there are a few things that I find very frustrating.

when drawing a simple shape as a circle or a square/ rectangle, it seems really frustrating that you have to drag and watch the x and y dimensions to ensure an exact size, and yes that is even using a grid. Is there no way you can access the 'dimension' boxes and input the dimension you need.

then the next point once you have drawn artwork, how do you check or confirm a dimension, see the attached drawing showing the path how can I check what the x and y dimensions are, without moving one corner......I cannot do that all the time.

when I want to print a trial print how can I assure that it prints to scale / the exact size that I have drawn.

lastly how do I create text to millimetre dimensions, specifically in height

I intend to use illustrator to drawn decals to be used on models, that is why I need items drawn to very specific sizes, and then the drawings will be sent to a specialist decal printer.

I do hope you can point me to some tutorials that or that you are able to answer these questions.

Alistair