put the base down, apply silicone generously where the pannels will cometogether and fold together, adjust with a framing square and hold in plasce with a GOOD masking tape.
press the panes together hard enough that the silicone oozes out but not hard enough that it all oozes out, and once its presed together dont let it go, air might get into the seam. once all the pannels are up and taper inplace you can apply a bit more silicone on the inside and smooth the inside seam out into a nice V although the silicone inbetween the glass where the glass meets has more to do with the strength and water retention of the tank then the inside seal. but this never stops me from maskin off the unside and sothing it out anyway, then lifting off the masking tape to reveil a nice straight seam...
i do use clamps and lightly clamp the tank intoplace then apply tape to hold it together but you dont have to.
all you need is silicone no other glues, GE I or GE II(without bioseal) work realy well, its the same as the allglass stuff the lfs's carry.
then you let the tank sit for a week, and no shorter then 3 days. test fill, empty place and enjoy.