Navy Movement

I have a landlocked country but right next to me is a big lake when I create a navy will it go into the lake or the ocean and can I move it between the two....I know you can put navy units in the lake because one of my neighbors has 3 fleets in it but I'm wondering if you can move them out or what's all that about.....thanks

It won't make a difference. You'll be able to move them anywhere there's deep water.