I know the other guys here have provided some info on order of operations, and I'd like to add my own experience learned from making mistakes to the mix. Like unterhausen suggested I've also found that building ST-BB and then HT-DT as two units is the way to go with limited tools. This way you can more easily correct mistakes in the front triangle before getting the TT in place, because once the TT is brazed in making corrections to the front triangle can be VERY difficult as this assembly is super strong. Also, a word of warning regarding pinning: Do practice joints and measure them. I've found that pinning isn't all that easy to do properly. Getting the pins placed so that they lock the tubes in place can be quite difficult and if anything moves on your during brazing or while moving the frame out of the jig and your joint is crooked it can be a lot more work to make a correction since your joint is full of holes that might be in the wrong place. I've found tacking at the lug tips to be faster and easier than pinning, but for the newbie like myself there are dangers here too. If you get enough heat into the joint so that all the brazing material is liquid and your jigs aren't properly setup (or if your completely out of the jig) the joint can slip and move out of alignment which means reworking the joint. Andrew's advice of pinning and tacking is quite good (he tends to give good advice!).