Oh man, you have a lot of reading ahead of you if you want to really know your way around these subjects.
But I should say something here. Training your plant is done mainly for two reasons.
The first reasons is that you want your plant to cover the whole area of your grow space and make efficient use of the lighting so you start bending the stems in order to make them grow in a a more horizontal direction rather than just up. So if like in your picture, you have 8 plants, I see little to no point in training as these plant nearly cover the whole growing area anyway unless your are planning to move them to a bigger area.
The second reason for training is that your plant height is out of control and you don't want it to bump into the overhead light and so you start bending the steams sideways to make it avoid hitting the light. With good planning, you can avoid this from the beginning. So you should prepare for a tripling of height as Peterstoke indicated above.
Now for topping. Topping is done to break the apical dominance of the plant which should provide you with more than one main cola and you can top more than once but be careful as each topping stunts the growth of your plant for a few days. I usually top my plant earlier than what shows in your photo but I would suggest you go for Manifolding which is a topping technique that makes your plants end up looking like a branched candle holder (and in the process, you give up all the smaller bud sites below).
Now for pruning, hmmm, there is a lot of disagreement on this subject. Some people don't prune at all and others prune too much. My suggestion is to only prune the big leaves that are shading budding sites below it at week 2 or 3 of flowering and leave all other leaves intact.