Absolutely everything you need to know about single seater spaceframe construction. Read it. Study it in depth. After devoting time and study, gaining a basis of knowledge that will allow you to ask questions based on expertise. Use search engines. A massive amount of material is available to anyone willing to do the work. This is a starting point. After study return with questions based on expertise. Your questions are so general they will lead to 200 pages on the Forum. Do the work. Research the FIT threads, a wealth of design information and recommended texts specifically on spaceframe construction is on the F1Technical Forum. Contact the author of the link below. Race Car Engineering/ss collins have run multiple articles on FSAE and space frame formulas. The text referred to in this dissertation, on spaceframe construction > Racing & Sports Car Chassis Design by M Costin can be bought on the internet for as little as 6USD or a pristine copy for 2400USD. Search for it. Buy it.
Formula SAE-A Space Frame Chassis Design Dissertatioin by Christopher Scott Baker, University of Southern Queensland, 2004
http://eprints.usq.edu.au/39/1/christop ... R-2004.pdf
Everything you need including structural anaylsis with formula from M Costin book included in the above PDF
This site features a series of pictures under "Construction" showing the entire procedure of building a complete chassis jig/bench then building/welding a space frame chassis from begining to end.
Now build your spaceframe chassis
Just do it
EDIT - The last GP/Formula 1 spaceframe chassis were built from - " Twenty five ton mild steel is quite suitable for welded tubular structures of the space frame type, but some manufacturers use a material which approximates to aircraft T45 specification, a maganese steel alloy which is particularly suitable for welding" - M Costin - The "Cos" in Cosworth.