Regaine / Rogaine Application Process Question (male pattern baldness)?

Hi, i’ve recently purchased regaine, I just don’t know what applicater to us. They have give me a choice of the spray, the roll on or the long nosel spray.

My hair does not have a bald patch and I have hair coverage all over. However i’ve started to notice I can see my scalp, (so basically my hair is getting thinner). I think its the nosel spray I need but where do I spray it if I targeting the whole top of my scalp. Also does it matter is my hair is long as im thinkin the concentration may not be able to reach my scalp properly.

The main question is how do I know I am applying regain properly?

Thank ou