When you finish model , set it up as you like (you can upload model w/wo material setup , w/wo textures etc.) If you have textures, create single folder, in that folder create another folder named textures and put all textures there. In blender applay textures (from that "texture" folder) onto the model in such way that when you open .blend file textures are automaticly loaded and applied onto the model, save model as .blend in that same folder where texture folder is. Than using winzip or winrar zip texture folder and .blend file. This zip file you upload here as model in it's native format in this case blender. Repeat this for every format you can get out of blender that's not problematic (obj, fbx, dae etc etc). Problematic= bad normas, bad scale, unnesecery triangulation etc. Render some preview images for presentation here on cgt but I think that's self explanatory. I'm not a blender guy but I think principle is the same. Good luck.