Getting frustrated, no idea whats going on

[Dexi]

I am new to SH, and particularly SH5... I have been trying to play for the past week. I managed to get past the first mission, sinking 50k of ships and find my way to wil...whatever. Now I am totally clueless. I have the missions for blockade up north of england and sinking 100k tons southeast... I go there, occasionally find a ship or two, they are really hard to sink, I am out of ammo quickly, I feel like I have no idea how to play. I watched a video of someone else and he had his deck gun firing without him in it. I didn't know that was possible. I'm so lost on everything in this game it's ridiculous. I can't seem to find a good thorough walkthrough or tutorial anywhere. Am I supposed to try to attack one ship and go all the way back to base? Even if so that would be fine, but I can't even get back to base without randomly sinking halfway there. I plot my course, and obviously do time compression so I'm not staring at nothing for 3 years. Halfway back, the game starts lagging and then I'm sunk and it doesn't explain why. Every time. I know this game can be good if I just understood what the **** was going on 10% of the time.