I cannot create a mesh (the dimensions are all set to 0 whenever i do try and create one) have am doing a 747 400 currently I have done all the bits up till the engines.

I keep on trying to add a new cylinder to make the engines of the 747 but it doesnt work in either edit mode and object mode, the dimensions are set to 0 on all axis and whenever I try and change it it wont let me for the cylinder.

However when I try and add a cube, it somewhat shows the cube and not the cylinder.

Here's the link to show all the dimensions are set to 0 and I cant change them.
https://gyazo.com/b4d058ce91745538a1c97e88cd8e2fbd
I'm not sure but i might try to add new Objects (Create Tab -> Cylinder)

(Actually, I would use a torus )

and join the whole thing later on. (Ctrl+j)

Problems:

the object may need three different textures, one for one engine, one for the other, and one for the rest. (i had such issues, i don't know if that happens)