Kriegsmarine original procedures

Hello all, I've been using the Enigma for some time now and I'm fluent at the Wehrmacht procedures. As A U-boat re-enactor (I use silent hunter 3 a lot) I try to do things as accurately as possible beyond what the sim gives me. I have uniforms (Including knight's cross) and everything. As part of this immersion I have taken up the enigma machine and use the simulator to send messages when SH3 never had the facility of such a device. However, by default I have been using a series of keysheets generated for each month of every year of the war but follow the system of giving you a kenngruppen and just simply making up a random trigram and using only a single bigram table. Only today I have looked more into the original procedures. I have gotten example materials of most of the books and have a whole K-buch. This is where my trouble has started. So far, I have gone under the assumption that you first get your message, and using the satzbuch, one would convert their statements into numeric form which would be shifted using a daily key that added onto the numbers with no carry over. These were then to be converted into letters once more. I'm not too concerned about this part and I'm happy to leave messages in plain text once deciphered. I am using M3 since I'm still in 1941. However the K-buch is where the trouble starts. From what I have seen and read, it is given with a series of numeric trigrams with a column of various three letter kenngruppen. Once inner and outer settings are set, I look at the schlusselkenngruppe for Triton and it gives a range of columns I can look at, for example my book says 561-620 or 251-320. Then I look at the verfahrenkenngruppe to deduce the second trigram which in this case is 1-733. The confusion now begins since I'm told I have to use the so-called 'Tauschtafelplan' which makes no sense to me since it gives a series of months and days, followed by corresponding letters. What do these letters mean if all the spaltenliste columns are all numerically arranged and there is more than 26 columns for the 561-620 range. So what do I do with this table? No one online has given me a straight forward step-by-step tutorial on how to do any of the actual original procedures. Most of this is guesswork for me. Everywhere I go online it's 'the operator used this book to do that' or 'the operator used that table to do this' then going on to not explain HOW they used the book or the table to do this, that and the other. For all I know none of what I'm doing is correct at all. What is the step by step rule to gain the indicator? 

Any help is greatly appreciated thank you.