I've smoked fish, using a few different methods.
Advice:
Every smoker is different. You need to "learn" your own set-up.
You don't need anything fancy (the best smoked fish I had was some pike, prepared in a metre section of Russian pipeline, with a welded steel plate base and a dustbin lid for a..... a lid

)
(We made a smoking rack from coat hangers and chicken wire, which stood inside, the whole tube was sat on 4 bricks and a fire lit underneath.)
More normally, we use a smaller square box smoker (about 50x30x20cm), into which the fish and alder chips go. Once smoke seeps out from under the lid, we give it another 20 mins and eat it.
Do you get anything like this in the UK?
https://www.google.fi/search?q=Savustus ... 76&bih=730
Or do you have access to steel plate and a welding machine?